You might not like the games im about to put in, but really, these games are quite good, and should be played whenever you feel like it.

1. Super Switcher
2. Super Mario Crossover
3. Punk-O-Matic 2
4. i wanna be the flash game (its frustrating but hey, it will at least help you out a bit if you were playing a Ninja Gaiden game... hey wait, when you play this game, think of Ninja Gaiden!)
5. Sonny 2

These are the games i recommend you playing. They are good, challenging and fun to play.

Creds to the people who made them! :D