1) A Cargo Truck can recycle rubble by docking at a GORF even if the GORF is disabled (idled too maybe? I forget).
2) It's hard to pull off, but if you time it just right you can order a ConVec to build a structure and, at the last second, change the ConVec's orders. The structure will be built (with no ConVec) and the structure kit will not be used up.
3) If an Earthworker is killed or EMP'd while building a wall, that tile will forever have an invisible, indestructible wall on it, and the 9 tiles around it cannot have walls on them.
4) I've been playing around, and while I may just be imagining it, it seems that if you somehow manage to EMP yourself, the effect does not last as long as if you'd been hit by an enemy's EMP. However, if you capture someone else's EMP-equipped unit (or get one through a trade) that player gets the "reduced EMP time" benefit if EMP'd by that unit.
5) "Food stores are plentiful" status only occurs when everyone is dead; I believe it should occur when food stores aren't changing. Check with Hooman.