While it's billed as a great way to improve your video game skills (this IS ThinkGeek, after all) the Xtensor Hand Exerciser is also great for pianists, guitarists, tennis players, golfers - any activity that requires strong and agile hands.

Each finger can be flexed individually. I imagine this would be quite a site; laying back on the couch, downing some high-caloric beverage while you're exercising your fingers.