Modals of probability and possibility
You can very easily practice this language point with videos. One way is to reduce the amount of information that the students have, e.g. by turning off the sound, turning off the picture, covering part of screen or choosing an ambiguous scene or still. Students then speculate on what is going on and/ or why. This can be turned into a game by students using the modal verbs to make their bets. For example, if they say "It must be a kind of time machine" that is betting ten dollars, whereas if they say "It could possibly be a way of creating monsters" that means that they only bet three dollars.
Similar things can be done with guessing what an ad is adverting, guessing who says each piece of dialogue, what referencing expressions in dialogue refer to (e.g. what is the "it" in "I pulled it but it wouldn't come off"), or unconventional ways that they use particular objects (with things like The A Team series or the Home Alone films)
Reference expressions
Give students dialogue from the film with expressions like "one", "that" and "hers" in, where the meaning is not absolutely clear from the information you give them. Students have to guess what those things refer to then watch and check.
Countable and uncountable nouns
The students are given worksheets with sentences about things that are sometimes countable and sometimes uncountable, e.g. "There is some cake" (rather than "There are some cakes") and "There are some chickens" (rather than "There is some chicken") If they think at any time that a sentence on the sheet is true about that part of the movie, they shout it out. They get one point if it is true or lose one point if the thing on the screen is different. Alternatively, you could give them pairs of similar sentences and get them to compete to call out the right one first.
There is/ there are
Students make as many There is/ There are sentences about what is on the screen as they can when the video is paused
The same as above, but being allowed to talk about anything that has happened in the film up to that point (maybe with "There have been... so far", but "There are... in this film" is also possible)
Students predict how many kisses, slaps, deaths etc there are in the scene or whole video and then watch and check. This could tie in well with discussions of on screen violence etc
Reported speech
Give the students reported speech versions of what some of the characters say with some of them changed so that they don't quite match what is said, e.g. "He said that he had loved her" for "I love you". Students have to listen to the dialogue and mark each one with "Same" or "Different". They could also try to guess which ones don't match before watching
Using a video with quite minimal dialogue, watch it with subtitles and no sound. Half the students face away from the screen, listen while their partner explains the dialogue in reported speech and tick the sentences that match on their worksheet (which can be given as direct or indirect speech, and can include sentences that don't quite match to make things harder)
Give students a plot summary with inaccuracies in it, and get them to use reported speech to discuss the corrections at the end, e.g. "The text said that he wasn't the murderer, but actually he was"
Do the same with reviews with views in, asking students to disagree with as many things as they can (maybe for points)
Students roleplay a dialogue from the film before they see it (maybe from roleplay cards), watch to check any differences, then use reported speech to describe any differences between the two dialogues
Students watch a film in which the person speaking is lying, e.g. someone on the stand during a court case. They say what they think was inaccurate using reported speech (e.g. "He said that he had never met that person before, but I think they were lovers"), then watch the scene where the truth comes out and check
Infinitive of purpose
Students guess why characters do the actions you have listed and then watch and check
Students guess what the characters do to achieve the things you have listed, then watch and check.
Students match the actions on the worksheet to the purposes, then watch and check
Students make as many sentences as they can with infinitives of purpose while they watch the film
Relative clauses
Choose several things in the film that students definitely won't know the name of, e.g. a tow bar and fingerless gloves. Give them definitions of these things written with relative clauses, plus maybe a few that are similar but wrong or are of things that don't appear, e.g. "It is a white fabric thing which grannies put on the arms of sofas to stop them wearing out" for "doily". As soon as students see that thing on the screen, they read out the definition or just shout out the number of the sentence. You can also do the same thing where you give them the definitions and names and ask them to shout out the names.
Other language points
Functions
Students are given cards with the names of one or more functions on, e.g. "Request" and "Complaint". They watch a segment of the film with no sound and shout out when they think someone is saying something with that function, guessing from the situation, body language etc. Before they watch again with the sound on and get points if they were right, everyone can try and guess the exact words that are used.
Students hold up a card or shout out the name of a function that they think will be true of the next piece of dialogue, then continue watching and check
Colour vocabulary
The students are split into pairs. Half the students face the screen and the other half face away. The students facing away are given a worksheet that is a scene 5 or 10 minutes into the film but with no colours. As the students facing the screen watch the movie, they describe all the colours to their partner, who colours them in (with colouring pencils, crayons or felt tip pens). At least one thing on their sheet should be something they can only colour in when their partner sees exactly the scene that is on the worksheet, but other things like characters can be coloured in as they go along. Any student who thinks they have completed the whole sheet can shout out "Finished". They get ten points if all the colours are correct, but get minus one point for each wrong colour if they aren't all correct.
Students predict the colours of particular things in the film and then watch and check
Students predict what things of each colour will be in the film and then watch and check
Adjectives
Students are given a poster of the film with no writing on it and should add words or sentences to "sell" the film to people who see their poster.
Students use as many adjectives as they can to describe the scene when you pause the video
Students guess the personalities of the characters from their photos and/ or descriptions (jobs etc), then watch and check
The same as above, but asking students to write down an action or piece of dialogue that illustrates each personality word
The same as above, but with feelings
Students predict what the characters will do or say from descriptions of their personalities and a description of the episode, and then watch and check
Numbers
Put up a number (as a figure or a word) on the board and then play the film until that many something is on the screen, then pause. The first person to say the correct sentence with that number gets a point. This can also be done as writing or by selecting words from cut up pieces of paper to make a sentence.
Pause the film and give one point for each correct sentence with a number greater than one.
Phrasal verbs
Give students descriptions of what people do or dialogue from the film that includes phrasal verbs but has either the preposition or the verb taken out. Students predict the missing words and then watch to check
Give sentences describing what happens in the film or bits of dialogue that include phrasal verbs, split so that the verb and preposition are divided from each other. Students try to match the two halves, then watch and check
Reading
Give a huge list of vocabulary, including words and expressions that are and aren't in the video. Students have to shout out or cross off any that they hear (skimming and scanning skills)
Similar to above, but with sentences
Give a description of the film that has some inaccuracies in it, and get students to correct it as they watch
Do the same, but with character descriptions with inaccuracies
Give students one or two reviews and ask them to find as many things that they can to disagree with as they are watching the film
Give students a few reviews and ask them to find the one they most agree with as they are watching
Give students of several different videos with the more obvious clues taken out. Students race to work out which review is for the video you are watching. This works best with different episodes of the same series or sequels
Listening and pronunciation
Get a bad pirate copy of a film or TV programme with dodgy English subtitles and ask students to watch and listen for when the subtitles don't match the dialogue. The same is possible with proper English subtitles when all the words wouldn't fit on the screen etc, but it is more common and more amusing with pirate versions. Alternatively, you could set up your own version by writing the subtitles yourself (fairly easy with modern software, if somewhat time consuming)
Give students a list of words that appear in the film with their homophones, e.g. hair and hare. Students must listen out for the words and work out from the context which of the two words is being said
The same as above but with minimal pairs, e.g. listening out for of/ off and working out which one it is from context and pronunciation
Ask students to guess which word a character is saying from the shape of their mouth with the sound off, then watch again with the sound on and check