This is a fun, one-player, self-described 'lunchbreak' Flash game. I enjoy the heck out of it.

And if AQ isn't enough, they've got a new game!
DragonFable

And for the mecha-lovers, they've got a third game!
MechQuest

And now Artix Entertainment has a Flash-based MMO!
AQWorlds

AE has a bunch of mini-games too.
EbilGames

Remember the Infocom Hitchhiker's Guide to the Galaxy? Play it on the BBC's Radio 4 site!