EASY: Typing Adventure Level 1
http://www.learninggamesforkids.com/keyboarding_games/keyboarding_games_typing_adventure1.html
MEDIUM: Cup Stacking
http://www.learninggamesforkids.com/keyboarding_games/keyboarding_games_cup_stacking.html
MEDIUM: Balloon Popping
http://www.softschools.com/games/typing_games/balloon_typing_game/
MEDIUM: Super Hyper Spider Typer!
http://funschool.kaboose.com/gamesFiles/flash/kaboose/spidertyper/spidertyper.swf
IMPOSSIBLE: Axis of Evil
http://www.auntlee.com/kids/axis_game.html