Wordpress Theme To Have Website Run By Users

I'm looking for some wordpress them as it states in title. I would like to have something like Damnyouautocorrect. c(o)m, epicfail. c(o)m etc. Basically I would like to users to register and add their own pictures and videos. Do you guys and gals know any wordpress theme which would meet my needs? Thanks in advance.

Allow users to register and have it auto grant publishing level.

Maybe there are some plugins...?