One day I wanted to test out factorization's wrath lamps. At first I only made one and installed it in our central crafting area. I was quite impressed with the bright bundle and decided to replace the torches with more wrath lamps. The first lamp left some shadow near one of the walls, so I decided to move it a couple of blocks. It didn't come down when I hit it with my diamond drill, so I shot it with my mining laser. I didn't double check my laser setting, but the hole in the ceiling wasn't deep, so I wasn't concerned.
A couple of minutes later someone noticed that the library, that was a couple of floors above the workshop, was on fire. It housed our enchanting table, mystcraft books, loads of cosmetic bookshelves and was completely made out of wood. By the time we managed to put out the fire, it was half ruined.
At first we did not understand what had happened, untill I noticed a hole in the library floor. It turned out that my mining laser was on long range and I didn't shoot completely straight up. One of the wood blocks at the exit caught fire and burned the place down.
An hour earlier I burned down all the grass and trees in our courtyard when I made the dark iron. I had to promise to stay away frome fire and explosives for a while.