I’m kind of excited about this now, I spent some time learning the UTeditor to create models and maps and such a while back. Certain issues that kept me from pursuing it further I believe, may have just been resolved.
I just discovered this today/yesterday, they released Prometheus on the UDK 7-11-09.
I don’t want to give away any details, but It shares a certain similarity to Portal and expands in a much different direction. It follows a gameplay much like a very certain Spanish film titled Timecrimes (2007) http://www.imdb.com/title/tt0480669/ which is also good too.