Avara. What a game from the cool folks down at AmbrosiaSW. This is perhaps the best shareware game ever made. It rivals commercial games, and it only costs 20 bucks. So, why the praise?
Avara is a 3D internet battle arena. You are in a HECTOR (I forget what that stands for. It does stand for something) and you fight against other HECTORS. You can play over a simple internet connection, but most people require something equal to or above a 33.6 kps connection so that there isn't jerky, slow play atmosphere.
Your HECTOR is armed with grenades, missles and boosters. Grenades are the hardest to aim but the most effective. You have the choice between a light, medium and heavy HECTOR, the difference being the amount of ammo you can carry and the speed with which you move.
Also, there are a TON of extra levels for the game, making play always different and interesting. There are sometimes tournaments, which are always fun. There are also a lot of really nice people on there, though there are some assholes. If you ever do go on there, look for Rush (that's me). I really advise you to try the game: it is great.

I have four screenshots right now. Here they are:
Number 1
Number 2
Number 3
Number 4

For more on Avara, visit either the

Avara Website
or
Ambrosia's Avara Page