Mashable says it's "the video equivalent of Instagram": the newly launched Vine is cool — and could be super creative — assuming, for the moment, that you've got iPhones or iPads in your classroom (there are still few in any classroom I'm associated with).
Of course, there's not a lot of language that you can cram into the six-second limit (though it would be fun to see who can get in most!). But it's like podcasting: there's so much more language practice to be had if you have learners brainstorm and rehearse and have someone playing the role of "director".
If you don't have iPhones, you could always use any mobile for making the videos and the learners could always share them directly in their hands, on their phones. You might want to extend the time limit — but keeping it short is part of the challenge.
With podcasting, similarly, I like to have my learners keep to under 2 minutes for anything they record.
A very tight word limit also makes for great creative writing projects:
Short, creative writing projects with Twitter, Edmodo
Short, short stories
Mini-sagas and 100-word stories