Thanks to this post: ThinkPad X61 Tablet Tilt Detection and Ubuntu Karmic Koala | Karol Krizka
I now have tilt detection on my Lenovo x61 Tablet, and it's awesome. I think I'm gonna see if I can make one of those marble-style games using the orientation sensor, because that would just be cool.
Or use it for various other types of control. Awesome.