Here's a little thing I found while I made this simple, triangle shape drain on a map. It would seem as a bug when you jump into it. You start to slide on it.
And the fun part is that the more you move the direction you are facing the more speed you'll gain, like infinitely(tested about 17000 units long drain)!
You can't normally jump out of it, but you can laserjump your way out of it(if not too much speed). As it is hard to explain here's some graphic:

(water is not required)

And the other fun part of it is that you can go up the hill like this with increasing speed! I tested 10 degree angle which works and 30 degree angle which I believed can't work anymore and it didn't.
So the maximum angle is somewhere between 10 and 30...

I was trying to think use for this feature and got the idea of a player launcher of some kind. Just ad a jumppad in the starting end of one of this drains(in an angle) and make the drain quite long.
You'll jump like never before

I don't know if this is a known thing. Call it a feature or a bug but it's somewhat fun

Heh, i have seen this done in a W:ET trickjump map, and they made curves using patches also. I think its because when you touch stuff more than 45 degree angle, you have no friction on it, so when you place to together you have no friction and slide

seems funny

sounds like.. SPACE MAP!