Somebody obviously had a few too many at the nineteenth hole before coming up with this idea.

Plug your Putt Returner into your computer’s USB port. This will automatically activate the game. Place the ball on your desk a short distance away from the Putt Returner and carefully line up your putt. Strike the ball smoothly with your miniature putter. If you hole your putt the ball will be sent right back to you!
Vary the distance and angle of your putts for a never-ending challenge!

The USB Putt thingie can be yours for £9.99 (~$20).