These will all open in a new window so it doesn't clutter up my script here. I've played all these games, so I know they're pretty good. Have fun!

Battleship
A nice Javascript version of the orignal Battleship game. Loads of fun!

Concentration
Classic memory game.

Dots
Connect the dots one line at a time and try to get more boxes than the computer.

Falcon Fighther
A great little action game that's absolutly amazing!

Peg
Jump pegs to try to clear the board of ever peg but one.

Towers of Hanoi
Move the disks one at a time to a new post. Hard, but addictive.