Disco Inferno
On the official Happy Tree Friends website. It's the kind of online mini-game you can totally squander a significant proportion of your morning playing. Of all the online games they have available, I'm naturally most drawn to this one, since I get to play as my favourite HTF character. And that's awesome.
It's quite simple, really. You just have to use your mouse to direct Disco Bear around the dance floor, catching the falling white musical notes and scoring points. Those red flaming ones...they're not your friends, and are best avoided at all costs. To get hit will result in an increasing amount of bodily damage as the game goes on (this being HTF, don't expect the outcome to be entirely pretty). As you can see, I've already started failing on poor DB in this particular round and caused one of the danged things to become lodged in that fabulous orange afro of his, but then it was pretty hard to stay properly focussed upon controlling the mouse whilst taking a screenshot at the same time.