There is a Demo for the 3D capabilities of the G1 on market. It's called Neocore and was made by Qualcomm to demonstrate the power of the G1's graphical chip.
There's also a video about this for people who don't have a G1 (like me).
Apparently this demo showed Google there's a problem with their OpenGL stack in Android, which makes the open GL work less fast. So when they fix this, the fps should go way up!