There is actually one map that does climbable walls as far as i know. It's called Matrix Lobby i think and it allows you to do "matrix tricks" like walking up walls and so on.
: Ok. First I'd like to say that I didn't plan on entering this map into the
: contest when I was making it. It started off as an experiment (which
: apparently failed) to see if I could make "climbable walls." I
: personally had never seen a map with the kind of architecture I was
: planning on using. Apparently, this was too much for forge to handle, as
: it doesn't even work in visual mode, but strangely aleph had no trouble
: running this map unmerged. A couple hours before the deadline of the
: contest, I decided to enter the map for the hell of it, since I had played
: it with some people that enjoyed it. I wasn't sure if it would be
: disqualified, but I figured I had nothing to lose by entering my map.
: You said it crashed for you when you tried to run it, and I noticed that this
: only happens on 1/18. If you use a nightly, you can at least look at the
: map. However, it will still be very glitchy.