Here are a few of the better Shockwave/Flash/Java games I've played online in the past few months.
Pitfall! (
http://www.langleycreations.com/pitfall) - Unofficial remake of the nearly 20-year old Atari classic platform title. Just as insane and addictive as ever, recreated down to every last detail.
Electrotank Games (
http://www.electrotank.com) - This site makes some sweet games; I'm really fond of their minigolf and airhockey games. The MiniGolf game has multiplayer capabilities; pretty advanced for a Shockwave game.
Kill Your Friends (
http://www.b3ta.com/kill) - This fun and mildly disturbing game consists of you uploading a picture to their server and then proceeding to shoot at many copies of the picture in a Space Invaders-esque environment. Due to foul language and simulated "violence", this game isn't recommended for people with moral fiber. Or friends. Important: Do not really kill your friends. If you have any.
Well, that's my list for now. There are a few others that I can't find the URLs for at the moment. Share some of your favorites!