Minecraft mod lets you think with Portals
This is no simple mod - this is Extreme PortalCraft, a new map for Minecraft featuring - you guessed it - a bunch of Portals.
Showing some serious dedication and love for both games, this mod is available in two parts, which transform the Aperture Science Handheld Portal Generator into a collection of blocks.
There's heel springs, test chambers and handy energy pellets, and a familiar-sounding robotic voice narrating your moves.
You can follow the development of the map at the Minecraft Forums, and download the files (and everything you need to run them!) for free.
Surely, this combination of two of the greatest games we've seen in a while deserves your full attention - go check it out!