While you're waiting for Project Natal and Sony's motion controller to arrive, Sky has just the thing for you: Webcam games. As the name implies, these games are controlled using not a controller, but instead track motion via a webcam.
Running in any browser that can handle Shockwave, Sky's webcam games aren't exactly going to pose a threat to Crysis or Call of Duty 4, but then players of such titles are hardly Sky's intended audience. Rather, Sky is targeting gamers that fancy flapping their arms around a bit to get a bird to fly, or swim a couple of lengths of a swimming pool.
Currently only single player games are available, but a two-player "Sumo" game is supposed to be 'coming soon' suggesting a reasonable level of versatility to the tracking method used, even despite being simple enough to run with any webcam. Given most PC users in Sky's target audience will have a webcam - it's probably harder to find a laptop that don't offer one - not requiring dedicated hardware is clearly a boon.
I'll be sticking to my keyboard and mouse for my PC gaming, but if you're feeling more energetic then by all means, knock yourself out.