Forget quadratic equations, play 'Super Smash Bros.' on your TI-83
The geniuses that guided Rosetta's lander onto a freaking comet no doubt put their TI-83 programmable calculators to good use, but you know what the rest of us were doing with them? Yeah, playing Wolfenstein. Now you can misspend physics class with another game: Super Smash Bros. Programmer Hayleia managed to port it over to the TI-83/84, and even left the code open for anyone to modify. It has a great zoom effect to make better use of that low-res screen, though for now you've only got Fox and Falco to play with. Yes, yes, we know that there are brand new versions of Super Smash Bros. for 3DS and Wii U (soon) with over 40 playable characters each, and you should totally try those. Meanwhile, you've got something to do (while appearing productive) when your trig prof hits a new level of boredom.