Create a brute and pit them in a fight to the death! It's a pretty fun game that requires maybe 3 minutes of effort a day. The fights are automated, you just sit back and watch the cartoony figures whack each other with bamboo poles and knives.
You don't need to register at all, but if you want to be the only person to use your brute, you can just put in a password. There are a few simple attributes and skills they have, it's nothing fairly complicated.