Glass2k - Small little program that allows Windows 2000/XP users to make any window transparent.
PiPer - A DIY Minecraft computer to build gadgets
WindowTop - Easly set any window on top, just move the mouse to the top area of the window.
PiP for Mac - Always on top window preview similar to the popular windows only OnTopReplica
DeskPins - DeskPins can be used to make any application topmost, that is, to keep it above all other windows.
Helium - Helium lets you accept payments by credit card for anything you want to sell online.