That there is Homestuck, which is a completely different beast. Though it begins quite low-key, the particular adventure eventually fans out into a science-fiction epic with several dozen important characters, hours of animation, days' worth of music, 500,000 words, and 5000 pages and counting. It's the current adventure, and has been going on since early 2009.
It should have some sort of cohesiveness, or at least basic premise. The first MS Paint Adventure was about a guy breaking out of jail. Why not have a similar, simple set-up with a clear object? It can still be totally random.