If you've played Android games, you may have noticed the presence of a service called OpenFeint.
This is somewhat similar to Game Center on iOS in that it has a friends list, achievements and leaderboards.
You would've automatically been assigned a random name of Player <random numbers> if you've played an OpenFeint enabled game. Check your OpenFeint settings (accessed by pressing the OpenFeint icon - it looks like two leaves) and claim your name (don't forget to set up account retrieval for when you get a new device).
Toss your OpenFeint names into this thread.