Many have (falsely) accused the "Flip3D" feature in Windows Vista of being a rip-off of Mac OS X's Exposé. It's not: Flip3D is simply a 3D version of the ALT+TAB task switcher shortcut that's been in Windows for decades. (Put another way: Where Exposé offers additional functionality related to locating individual windows in running applications, Flip3D only provides access to each application.) As you might expect, however, various people are looking to replace Flip3D with something more Exposé-like. Here's what looks like an excellent example:
Neat! I'll try to test this soon to see how well it works, but the developer tell that a stable version will be out in about two weeks.