Let's face it, their so easy even a hippo could make them - cue Grot!
Well, there you have it. It doesn't take long at all to build up a nice collection of ruins - especially if you have a few mates to help you. You can quite easily set up a porduction line - I tend to build the shells of several ruins at once, then add the timber frames to them all at the same time before moving on to the paint stage. That way you can almost always be working on one of them while the others dry.
Don't miss Ishoo Sicksteen - Toxichem Ponds coming soonish (I have a fiendish Sci-Fi diorama to build before I start it)