Terragenesis has an article on building laboratory equipment for mad scientists. The photos show an amazing use of various household and electronics bits.
Tim’s Wargaming Blog has a photo tutorial on making “36 Miles of Barbed Wire.”
Matakishi has some instructions with photos for making World War II era buildings out of sheets of cork.
Terrain Thralls has a photo tutorial on making terrain that looks like ice floes. They’re cleverly made from foam core, and is intended for Privateer Press’ Warmachine game, but I think it would be spectacular in a variety of fantasy settings. I can also envision a neat Frankenstein vs The Monster scenario.
Sculpey is a polymer clay that hardens in the oven at relatively low temperatures. It’s amazing stuff that can be used to create a wide variety of useful things for wargames. Here’s a tutorial on using sculpy to model slate.