Not officially, mind you, but then unofficial unions in PC gaming can often be better than the "real" thing anyway.
Eugenio "Motanum" Roman put the mod together, which recreates the Aperture Science Labs from Portal (at least in spirit) and makes a passable Team Fortress 2 map out of them. While you can't use a portal gun, GLaDOS features, as do those little balls of energy that killed you instantly in Portal (and they kill you instantly here as well).
The map is available here as a 34MB download.
Don't expect a polished affair from it - it's a little long and a little bland in spots - but hey, it's free, and it's a Portal map in Team Fortress 2. There are plenty of people who a combination like that will appeal to.
[via PC Gamer]