Here's how to make a shortcut that will open about 100 command prompts leaving the victim to have to close them all... one by one.
#1 (follow only if XP user) - Right click the taskbar and click properties. Uncheck the box that says "Group similar taskbar buttons" and hit OK.
#2 - Open Notepad and copy and paste "start" (without quotations, space them out, too) about 100 times (the more start's the more windows to pop-up). At the end make some weird message like "you_smell" but make sure that there is a "_" instead of a space.
#3 - Save it as something like "cool.bat" or something but whatever it is, you have to add .bat to the end.
#4 - Open My Documents and find where you saved it. Right click it and click "Send to... Desktop". That will make a shortcut for it.
#5 (use this step to REALLY tick them off) - Open the start menu. Find "Command Prompt" and right click it. Click properties and click the Options tab. Check the "Full Screen" box then click OK then (if popup box appears) click "To shortcut". This will make the computer unusable for about a minute THEN leaving them to have to close every single command prompt.
If you decide to test the shortcut and you want to end it without closing every box: XP - just undo the first step. Earlier - Hit Ctrl+Alt+Del and highlight every task that says Command prompt by dragging your mouse from the last one to the first one.