I cosplayed as Ryoga Hibiki from Ranma 1/2 at otakon a few years ago, both his regular outfit and his outfits from the OAVs
I won a judges award and got a free Tshirt for this one, which is based on the OAVs: (for those who haven't seen Ranma 1/2, I'm teh one on the right)

this second one I did an actual skit on stage with an Akane cosplayer, which I wrote the script for. It was hard to tell if we were speaking loud enough for the audience to hear, and I never did find out how well we were received by the audience. I think ultimately we got overshadowed by people who actually rehearsed their skits together and were cosplaying as more recent and better recognized anime than what we were doing. There were some seriously awesome skits.
Still, my costume got me a picture with this girl, who I THINK was apparently cosplaying as Chocolate Misa (good cosplay is a truly beautiful thing)

No, I'm not on drugs, just tired and overheated from attempting to play DDR while in that costume, which is where I bumped into her.
The two most awesome parts of my costume were the Umbrella and Pchan:



Starting Pchan:

Ending Pchan:

He squeaks too, and I think that really won over some of the judges. :P