Loadsa games

Suburban Brawl is an excellent game which I found on a site stuffed full of simple games. The Experimental Gameplay Project has games which were made in less than 7 days. They did 50 in one semester and now they're onto version 2.0. It's really good. Some are .EXE files and some have .SWF versions whcih obviously make them a little easier to play 'on-line'... I'd recommend a look.

That must be the next 50 '5 minutes' taken up!

Dirty Harry Game

The Dirty Harry Game on the gorillaz site is a frustrating but entertaining 5 minutes play... Drive the car round, collect the kids, get the band member and get back to the helipad.
I only managed to pick up 2 kids. Not that great really...

Music quiz

Try out this music quiz to see how good you are with recognising instruments, music theory and classical styles. I got 9/10.

Blue Ball Machine

The Blue Ball Machine is just crazy! It'll take you 5 minutes to figure out what's going on! Thanks to Jon for this recommendation...