It has been a bit since I've built terrain.
However, I recently bought 50+ pounds of Robotix toys off Craigslist and I've been working on some terrain for a friend.
First two pics showing Robotix parts assembled (some cutting required) with bingo chips, pathology specimen case lids, Leftover game tokens, and various other bits.
Last pic shows complete after few layers of spray paint and a single drybrush. Very good chance I'll be building similar versions for myself. Really happy with the results here and it was an extremely fast project.