Over on steam, there is a massive group for Friendship is Magic. If you haven't joined it already, and you have any presence at all on steam, I would definitely suggest it! There are already more than 4000 bronies. They have servers for just about every multi-player game around. You can find it below!
MLP Steam Group
Also Star Wars, the Old Republic has opened up pre-guild creation on their site, and a pony guild is looking for members. You can find that below, along with the ponychan thread.
FiM SWTOR guild