The TI-83 Plus series doesn't have a touch-pad like the TI-Nspire series, but Deep Thought has decided to mimic one in his recent demo port of Fruit Ninja, originally released on iDevices!
In his version of the game, you basically use the bottom of the calculator as some sort of touch-pad. Basically you swipe across the keys (although unlike a real touch-pad, you need to press them in the process) to slice fruits jumping in the screen. Unlike a real touch-pad, though, you must actually press the keys, but it's still a quite innovative control scheme for a TI-83 Plus series game.
The only downside of this method is that due to how clunky the keys are on TI-84 Plus models, playing the game on it will be extremely noisy, to the point where it might annoy people surrounding you.
Note that the noise caused by swiping across a 84+ keypad is not this bad, though. The video of the game in action kinda parodies that only downside of it.
You can download Fruit Ninja for calculators
here and the topic to discuss it is available
here!