Here's a "hack"... in the id maps!
I was zooming around e1m4 when I noticed a funny looking block with an Ogre walking into it... Using sock's mod with path's visualized to show what is up:
http://scampie.net/etc/ogrepath_wait.jpg
Turns out, that block is a func_door on top of the first path_corner in a sequence the Ogre is trying to walk to... so it can never reach it and ends up sitting there forever!...
Until a trigger lowers the block out of the way. The Ogre can continue to walk out the door and eventually gets placed into a path_corner loop on the dock over the water. The end result is like a scripted sequence of triggering the ogre to walk out of the door on demand!
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It's odd because it's very unlikely a player will ever notice this happen, the ogre walks so slow and the trigger that lowers the block is right at the edge of the water... In all honesty, if this were me, I would've just teleported that Ogre onto the dock when the player was out of view. But what id did here was make a basic scripted sequence with their primitive tools that only a few % of people might notice... But you might just hear the door open, and see the ogre lazily walk out and it makes the world so much more alive. It's wonderful :D