Spotted this earlier today...
http://forums.beyondunreal.com/showthread.php?t=194613...and downloaded it without giving it much thought.

I had one of the previous versions of the Portal Gun, which is a weapon mutator from the game Portals which I've never played. The concept is simple enough, for anyone that's ever read a Doctor Strange comic in the early 1970's or various other comicbook references I could supply.
The one I already had (PortalGunFTW) basically did this:

The one on the left is the 'in' the one on the right is the 'out'. Very fun gun, only lethal in creative telefrags or dropping a portal in somebody else's path and popping the exit way up high in the sky.
That and the portals look really cool!
I don't know what specifically gopostal was referring to in regards to server crashes...other than that. He didn't mention the specifics but ultimately that doesn't much matter. His version looks like this:

Not so cool looking but it works about the same.
Anyway, he wrote it as a .u file without an accompanying .int file, setting it up just for summons as he says in the included ReadMe. I've never written an .int for a .u before but if it's as easy as this was then I may have to do it more often.
Personally, I still prefer the one I had before but then I've never tried it on a server...though I have played with it on somebody or other's MonsterHunt server without any notable issues.
Enjoy!