Chameleon hides windows you shouldn't have open at work
Launch Chameleon and it tucks itself away in your system tray. Call up the main window and it displays all the programs currently running on your system, which you can then add to the hide group. Programs you add can be hidden completely with a hotkey (ctrl + win), and you can also set their transparency level. As you can see, the result is slightly less obvious than this kind of slacking off would normally be.
Chameleon is a free download for 32-bit Windows systems (it didn't play well with my Vista x64 install), and the .Net 2.0 runtimes are required. It's fairly light on resources, hovering around 9mb of memory on my desktop running the Windows 7 beta.