The unofficial roleplay server has been found more or less to be Virtue, but don't let that stop you. Rping in CoH 'generally' has to do with acting out the character (flaws/virtues/vices/quirks) of your hero/villain. My hero whose name I shamelessly stole for my forum persona is sometimes difficult to roleplay-he's a soul reaper(think grim reaper but exemp'd down a bit) who is actually a servant spirit of the King of the Land of the Dead according to roman mythology (Pluto that is) that has in the last century had two kheldian-esque fusions with humans from Earth (one was a Norweigan in his 20s at the start of WWII, the other I have not fully developed yet). Due to a certain semi-mystical law, he cannot 'unfuse' from his human host without them dying, and for them to die he must leave them. His mere occupation of their body means that so long as he needs to exist in the Land of the Living they are basically immortal. I've been forming this character since my forum registration date 
and still adding to him. The result is that when I roleplay him he tends to either talk a lot(manifesting personality traits taken from previous human hosts) or not much at all(falling back on more 'higher being' traits). A very complex character, to be sure. However I also have a hero and a villain copy of him(alternate reality) who I recently made. The alternate reality version is actually more fun to play as he has the personality of the hero, with a little more seriousness involved-he works for the 'bad guys' but doesn't feel like he's any more evil than the hero version does.
You could always keep it simple with the poor mutant viking who got sucked through a time/space rift and is coping with the present lol. The only real limitation to your rping is your own imagination. The basic rules are not talking about real world events as though they were happening in the game and when someone asks you a question or makes a comment you reply in the manner your hero/villain would reply based on their personality. Some people do the *ooc and talk about Real Life, or the ((man I hated that new <insert lame movie/comicbook/whathaveyou>, what'd you think?)). Some people are just die-hard perma-rpers...I can think of two and both are actually on liberty a lot hehe.
If you're looking for a place, I might suggest finding a 'local neighborhood' i.e. Kings Row that you like or that as you design your characters' concept(s) and use that as a basis, or if your character is from somewhere else then the first place they saw/realized they wanted to be a hero/villain in Paragon City/Rogue Isles.
Alright I've started an energy/empathy mutant character on Virtue, and gotten him up to level eight after some truly spectatcular teams. Now could someone suggest a godd rp sg?
Try posting or looking at the Virtue forums, if you haven't already found one.
I've recently become interested with the roleplaying side of COH, but I have no experience. Iwas hoping someone could explain what a coh roleplayer does, and perhaps a good place for someone new to start out. I've also heard alot about the unofficial roleplaying server. Some say Virtue some say there is none just lookign for clarification from more experienced players. I'm just a Bumpkin from Triumph all we do is smash baddies.