I joined the board recently, and I've really enjoyed all the maps that people have posted. Mostly, I'm deeply in awe of some of the wonderful maps that people have posted here. I hope to pick up some tricks from this group. But since we usually learn by doing, I thought I'd try sharing a simple map that I created a few months ago.
Here's a map of a subway car that I threw together for a Subways and Sorcery genre game. I based the dimensions off of a blueprint that I found on the Intertubes, but adjusted it slightly to fit on a 5' square grid more easily.
It looks good. I wondered if the seats are two small, but the math seems to work out. And it's been a decade since I've been in a subway anyway. :P