I'm not much into flash games, preferring multiplayer fps or mmorpg-style timewasting. But here are a few that I keep coming back to:

JellyBattle - A wierd turn-based multiplayer pvp strategy game. Probably the best flash game I have played

Tanks! - multiplayer pvp tank game

Insaniquarium Singleplayer but fun

Winterbells There's something very cute and appealing about this game, and it makes a nice xmas-time diversion. All of the orisinal stuff is worth taking a look at.

When I first read the post about the shift key disabling the "copy protection", I said to myself "I bet that is technically a violation of the DMCA." Now, I know this is rude to the student who published it, but I was semi-hoping he would get sued, so that everyone could see the lunacy of the DMCA.

Hopefully, the fact they "almost sued", will have at least some of the same effect (as in people going, "that is crazy, I need to tell my congressperson/senator to get rid of that silly law right now!"), without the poor kid having to go about putting up a legal defense.