There was this old game for Windows 95 called Super Pong 95. It had six game modes, ranging from classic to four-paddle...and Old West pong. In this game, paddles can fire bullets which can hit an opponent's paddle and freeze them for a second. In addition, if the ball hits a bullet, it ricochets and speeds up. Definitely one of the most fun variants of Pong out there.
Includes source code in Blitz BASIC.
Extract the zip file and run the executable. Windows-only.