Here is one I've found:
Got Brainy is a Perfect Site for Interactive and Visual Vocabulary... what a great way to add a fun flare to words!
Students can create aBrainyPic or a BrainyFlick. Simply upload a photo or video and add an original sentence or dialogue to demonstrate meaning of a particular word or concept.
If you don't want to create original content, feel free to just browse the submissions posted to enhance and encourage discussions surrounding vocabulary.