most complex/interesting linedef actions

What's the most amazing/complex/interesting linedef action(s) you've seen in a doom2 map (floor/ceiling changes, intersting stair building, light changes, etc)? Here is a submission by me anyway (doom2, zdoom, replaces map01, made in doombuilder):

http://www.sendspace.com/file/1jbitb

This was kinda hard because doom relies on adjacent sectors for height changes mostly. And sometimes even with dummy sectors it can be a pain to do complex things. Or you might have a group of sectors with sector tag '1', but then later you want only part of those sectors to do something else. I had to break down a group of 16 areas into both rows and columns as far as sector tag groups go, and sometimes you have to cross over 8 different linedefs at once to make something more interesting happen, while still allowing other things to happen in the future. Also there's a weird light strobing room that strobes as you walk and other stuff. There's no monsters (except a pain elemental that can't shoot anything), just stuff happening until you exit. Kinda short.