Someone built an Atari 2600 emulator in Minecraft

Runs at a solid 60 frames per four hours.

SethBling who has created many impressive things (a blocky version of Team Fortress 2, a Splatoon version) in Minecraft has created an Atari 2600 emulator in vanilla Minecraft. It may not be what you'd call playable as it takes about 4 hours for 60 frames to run, but regardless it's an impressive feat.

In this YouTube video the creator explains how it works and what went into creating it.

Thanks, PCGamer.