http://www.androidgamehacks.net/forums/
And just like hacking with Game Genie was unusual back then, jailbreaking devices, hacking .apk files and hand-editing save games isn't for everybody either. But all of that definitely still exists, and is far more accessible than ever.
The GameGenie/GameShark/ActionReplay scene was much more accessible than hacking .apk files and jailbreaking mobile devices. I was messing with those devices even before I decided on a CS major. And it was as simple as just having one stray thought "What happens if I change this number?" In contrast, you don't just decide "What happens if I open this apk file up and change such and such?" How many people even know that the apk files are just zip files to start with? Then you get into decompile the files or hex-editor or whatever... but none of that is accessible as just randomly entering a different number in the GameGenie interface that's presented to you immediately.