As I didn't receive anything really feasible in this thread
, I'm just going to go with something I think sounds cool. So, what I'm thinking is a collaborative drawing app.
There would be some number of rooms or channels with which you could connect. Each of these rooms contains a unique canvas and on this canvas all connected clients can free form draw. As a client draws it updates on all other clients. The canvas would be infinite in width and height and zoom and position on the canvas would be adjustable with two fingers. Each client can specify their color and would at least have primarily a freeform spline and perhaps structured shapes such as ovals, rects, etc.