I actually discovered this tip accidentally recently and thought it was appropriate for the Tips page, even though it's probably been a feature of Windows for years. (UPDATE: Sure enough, it's been around for a while. It's still a cool tip and proof that one learns something every day).
By default, the Windows XP Recycle Bin sits at the bottom right of the desktop, just above the tray notification area and system clock. If you've got a bunch of floating windows open, however, it's possible to obscure the Recycle Bin and make it impossible to drag files and folders there for deletion. However, Microsoft must have thought of this event, because you can automatically hide all of those open windows during a drag operation. The first time it happened, I thought it was a fluke. But it's not. Instead, it's a cool hidden feature of XP.
Here's how it works: Make sure a bunch of windows are open on the screen, with at least one of them hiding the Recycle Bin. Then, find a file or group of files you'd like to drag to the Recycle Bin. Pick up the files with the mouse and move them to the lower right of the screen. As you reach the bottom area of the screen, pass the mouse cursor over a blank area of the task bar, hover there for an instant, and--voila!--the open windows all minimize, leaving the Recycle Bin available to accept the dragged files. Good stuff. This tip also works when windows are maximized, assuming the file(s) you want to delete are visible in one of the available windows.