How many times have you found yourself frustrated by an iPad game's touch-screen controls? My personal answer: lots.
Take the awesome sci-fi/horror shooter Dead Space. As I noted in my review, "If there's a problem with Dead Space, it's the controls. They're about as good as they can be, but I usually end up fighting the controls at the same time I'm fighting the monsters. Oh, to have an actual game pad I could plug in!"
Ten One Design's Fling is not a game pad, but it's quite possibly the next best thing. It adds a small analog joystick to any iPad, thus giving you a physical controller for games that would benefit from one (and there are many).
The genius lies in the design. Held in place by a pair of small suction cups, the Fling employs a coiled plastic ring with a screen-conductive black thumbstick in the center. It looks totally bizarre, and your first reaction upon taking it out of the box is, "This can't possibly work!"
But it does, and quite well for the most part. I tried the Fling with N.O.V.A., Dead Space, Lego Harry Potter, Reckless Racing, and NBA Jam, to name a few, and almost without exception, it made games easier to control--and more fun to play. (NBA Jam in particular, which uses an onscreen D-pad exactly like what the Fling replicates, went from frustrating to fantastic--and it's not even iPad-native!)
What's awesome about the Fling is that it requires no special software, no batteries, and no connection to the docking port. Just slap it on the screen and start playing. When you're done, pop it off and stick it in the included soft carrying case.
What's not awesome about the Fling? For starters, it does slide around a bit, the inevitable result of robust thumb movement. What's more, in some games (like Reckless Racing) it's not easy to position the controller so it perfectly matches the onscreen controls. In other words, it may not work with every game you own. Plus, the stick often gets in the way of menus, and sometimes activates them accidentally.
I also need to gripe about the price. Ten One originally planned to charge $29.95, which was just plain ridiculous, but wisely lowered it to $19.95. Even so, that seems high for what is essentially a small piece of plastic. The good news is you can buy two (for dual-stick shooters) for $29.94, making your price-per-Fling a bit more reasonable.
It may not be perfect, but the Fling is an awesome way to add tactile controls to some of the iPad's best games. I'm joyfully rediscovering gems I'd abandoned just because the onscreen joystick(s) drove me nuts.