Some time ago I saw some online animated gif creator and thought it could be done in JS instead of Flash. We could easily access webcam from browser with the getUserMedia API. Nice tutorial about this API can be found on HTML5Rocks site.
So, getting image in real time from camera is easy with getUserMedia, but creating animated gif on client side was trickier part. Luckily, someone already made JS lib for that, and jsgif is great solution with really good documentation. All I had to do is to combine getUserMedia API with jsgif lib and I could create animated gifs with my face.