Created in one day with softcore images of naked women "shamelessly stolen from the teh intarnets," Mammary Advance is a homebrew Memory game for the GBA in which you flip two cards to literally match a pair. Interestingly, you're tasked with matching photos of left and right breasts instead of two identical images. This twist adds a lot more challenge to the simple game than you'd expect!
The sexual objectification in Mammary Advance is inescapable -- the only female faces you'll ever see are in the title and developer screens -- and we're, once again, left wondering why we can't have any sophisticated erotic games for our handhelds, but it's amusing to see that these immature releases didn't disappear with the rise of easily-accessible hardcore pornography on the internet.
See also: Naughtiness on the Nintendo DS