Or at least interesting stuff. In the US, Great Stuff is an expanding insulating foam sealant. You can get a can for about $5. I've been wanting to try it out for a while, and finally got some and made some test pieces.
I decided to make a little hut. I made the door out of plumber's epoxy and plasticard, and just set it in the side of a pile of Great Stuff. The Great Stuff expands, so I had to prop it up to keep it reasonably straight. My son asked me if I was making a brain! As I was painting the dark browns, I thought it looked like a diarrhoetic moose had defiled my gaming room. Still, when finished, it certainly does have some sort of appeal as a Sci-Fi hut of some sort, maybe like Yoda's in TESB. The other pile will be painted up as some sort of Sci-Fi ground plant. I want to make some quick foamcore corridors and line with this as bug holes or alien tunnel systems.