Portal in Minecraft
It's Portal, but in Minecraft! Are you getting this? Portal, the game that made the entire internet sing the same song for a whole year. Minecraft, the one-man project that's still selling a thousand copies a day without so much as a single advertisement. They got drunk, fumbled around, and this video is the result.
It's even got a Companion Cube! The main victory here is that getting this wonderful thing to actually work is so hard, it's convinced developer Notch to "add the ability for servers to download a custom texture pack to the client in Minecraft." That sounds like the beginnings of mod support, people.
Go try it yourself, go here.