A lot of my coworkers are hooked on the warcraft, but I can't see paying a monthy fee to play a game that I already paid $50 for.
I haven't played it in a while, but Nethack is a lot of fun. It's even more fun if you
play Nethack online. Although there is no direct interaction between players, you might encounter the ghost (and treasure) of someone that went before you. Online play requires connecting to the server using telnet, but I don't suggest the telnet built into winodws. Instead, try PuTTY or Token2.
I think my old standby is the
helicoptor game. which is good for one-button-fun.
Edit: I can't believe I forgot
Urban Dead. It's a low-tech (browser based) zombie game. It's a little slow going at first, but when you get a level or two and can actually kill something, it's a lot more fun. The server limits you to 160 moves per day, and 50 moves per character, so you won't spend the entire day playing it.
