Here are two sites which enable your learners to make fun animations.
Dfilm MovieMaker allows you to select your character (eight can be seen, left above), add what they're saying, etc, etc.
Using Dfilm's MovieMaker you pick from a choice of preset backgrounds, skyscapes, scenarios (rendez-vous, chase…) and characters, write their lines, add music and — in a series of straight-forward clicks, create your animation.
Once you've finished, you can send it to a friend — or yourself — which will then give you the URL (address), so that you can see it again.
ZimmerTwins (above) gives you just three characters to play with but some crazy additional features…
At ZimmerTwins you can create similar animations, though you've only (currrently) got three characters to play with. You can save your movies, watch other people's and comment on them, among other features.
Like Dfilm, it's very intuitive to work with — and kids will love exploring what you can do with it. The "How to make a movie" section explains all, if you are in any doubt (and makes good listening comprehension practice too!)
Note that you have to register (and provide an email address). You could get round your students doing that by registering yourself, and having them use your username.
Which is better?
Of the two, besides not requiring registration, Dfilm also has the advantage that your learners can input more text (important if you want them to be able to write some English).
On the other hand, ZimmerTwins seems to offer more "fun" features. If you've got really young learners, who don't know much English, it might be a better choice.
What would you do with these sites?
Make animations, of course… But what you really want is for your learners to get some language learning and practice out of it — and it's all too easy for the class to go silent (or real noisy!) while they fiddle with the animations but learn and practise zero English…
Providing them with a list of characters and features first and — in pairs — getting them to storyboard their animation first, before logging on, might be the best way to go about it.
When they do then get on-site, they will probably then have to discuss how they are going to adapt their storyboard to what the site can actually do — but that can only be a good thing!
What's the point?
For your learners, it's a fun, motivating activity. For the teacher, it must produce that language learning and practice.
If it doesn't, should you be using this technology…?
Note that you might need to upgrade your Flash Player (an easy download, provided you have "administrator permissions" on your PC/s, which you might not if you are in a school).