888888-in-1 (CoolBoy AEF-390)
888888-in-1 is a real NES multicart with a Gangnam Style themed intro, containing the majority of the song as a PCM sample. Yes, you read that right. However, the game selection screen has some nice music.
At 0x1803CA in the ROM, there are corrupted remnants of the original Gangnam Style MP3. The MP3 itself is corrupt to the point of no longer playing (only the header is completely intact), but the thumbnail, although heavily corrupt as well, can be extracted and viewed in an image editor.