Some pranks I made on C++. They are not malign, tough, they create a hilarious face on your friends. xD
Random cursor position virii: http://pastecoin.com/download.php?file=119
(binary | source with comments)
This is a great one!(Windows only) it moves the cursor to random locations on screen each time faster. It can be simply stopped by opening the task manager and killing the process. You won't regret this buy!(You may want to rename the exe to something like keygen.exe, [game].exe, etc.
Enjoy! Also, wait for more pranks soon! A beep on key press one is coming next!