Get to upload an image and select/outline at least the head area (but optionally body too)
Also have to define the line where the mouth is
Then turn it to a SouthPark Canadian-like character w/ the unhinged head and blocky appendages (using default blocky torso/body if they selected none)
Like the Saddam Hussein character from the movie, but without multiple real-image faces
Can do a lot now that you have a character
Pre-made dance moves...this is one of those neat-internet-thing-of-the-day type of ideas where people do it and share it for fun
Make a stick figure animator. This is a bit more involved and probably not as much payoff
Record microphone, and move mouth with recording. Can do novel things w/ web audio API like up the pitch Terrance and Philip style, or check certain sound values to determine mouth shape
Pre-made set of actions that people can't press like a sound board...farting, etc
Have to decide where state is stored...too much info for a URL probably, and I don't want to run a service for this
Overall, can be all client side (w/ blob API, canvas, web audio, etc) and would be a fun tech demo