You can also add Teflon skates to the bottom of your mouse, but you'd probably need a hard-surfaced pad. I've done this on my home and work mice, with different levels of success. The combination of new-model Logitech G5, Ratpad and what I believe are "Hyperglide" mouse skates that I have at the office is just incredible.
The skates linked above are white, but mine were black, so I'm not sure if this is the right set. But they are same shape; small circles. These have lasted longer than the special-shaped cutouts I have at home. I also use more than the 4 they have pictured. I've probably got like 15 on my mouse, and its now a freaking hovercraft.