If you do root it, I suggest getting some decent emulators. There's heaps of home-brew games that run on GB/NES/SNES/Master System/Megadrive emulators if you're worried about the legality. But there's also the "other" sort, where you can fit a massive amount of pretty good games on a microSD card or even the 6GB you have onboard. Like probably the entire collection if you want. Even the touch-screeny-ness of them isn't bad with the limited number of buttons required to play these games.
It's kind of like you'll have a 7" screen colour gameboy wherever you go. RPGs, strategy and sports titles are all really playable on touch screens, but even action titles don't fair too badly. Not too many buttons, nice touch-screen joypad, pause whenever-you-please function and save-game slots whenever you want. The older consoles don't require a heap of cpu power (way less than the kindle fire has on board) and you can while away your time reliving all the stuff you could play back from before you had kids giving you father's day presents.
There's also some pretty good older style computer emulators out there. C64, ZXspectrum, Amiga, as well as a host of others are all available in Android form.
Just off the top of my head, here's some good roms for touch screens (they ran perfectly on a friend's phone with a 4" touch screen, the kindle will just make that better. Old console graphics actually look pretty good when scaled down a fair bit). This is sort of a PC'ish list, but it's amazing all the stuff that they released on consoles at some time, and now they all run perfectly through emulators.
Pirates!, NES
M.U.L.E, NES
Ultima 4, Master System
Phantasy Star 1-4, Master System/megadrive
Uncharted Waters 1-2, Megadrive/SNES
Madden NFL '98, SNES/Megadrive
Mutant League Football, Megadrive
Simcity 1 and 2000, SNES
Lemmings 1 or 2, Megadrive/SNES
PGA Golf Tour (whatever year), SNES/Megadrive
Eye of the Beholder, SNES
California Games, Master System/Megadrive
Might & Magic 2-3, SNES
Final Fantasy series, NES/SNES
Cannon Fodder 1-2, Megadrive/SNES
Civilisation (it's a bit unwieldy, but it works), SNES
Tetris, GB
There's absolutely heaps of games that are pretty fun for portables. I've played them on an android phone, a tablet, and even my own Nokia non-touch screen phone (with an awesome 233Mhz processor, they ran fine). So do a search and look into rooting your tablet. The days of console yore awaits you. And they're all free and small and were good enough to enthral an entire generation of game-players. Some of them are even free and legal, which is good. So get a-rooting and have some fun. It'll get you way more out of the Kindle in any case, just from the "normal" Android store stuff.
Just make sure that you kids don't end up with your new pressy. Or use it as a baby-sitter if they're still pretty young. Now that's a father's day present!