Fling yourself. F-f-f-f-fling yourself. Wheeeeeeeeeeeeeeeeeee...
In case you need any encouragement to pick up Portal from Steam on Mac and PC, it's free! Still not enough? It's awesome! Need more? This video should help.
And it helps set the mood for the co-op sessions you'll take part in with Portal 2 later this year.
Video's below, thanks to D'Toid.