This morning on Nik's Quick Shout I read about Channel 4's Twist Our Words web page, where you can create video sentences that are 'mashed up' from a collection of clips of UK TV celebrities saying each word.
When you open the page, you'll see a lot of words. Start clicking on the ones you need to compose your sentence (or phrase), then click on the white arrow to create the video. When you're happy with the result, click on submit. You'll be asked to verify that you're over 16 years of age, and that you understand the terms and conditions of the site. Your video will be sent to the gallery, and you'll be able to copy a link to it, and the embed code for it.
Here's the one I made to see how it works:
The fun part and the hard part is that your choice of words is limited. You may not be able to write a particular sentence you had in mind, but it's interesting to be forced into choosing other words, and changing the meaning. It's sort of linguistic batik - your video won't be what you imagined before you started, but it will be an interesting result no matter what.
Nik Peachy lists several good ideas for teachers about how to use this site in teaching language.