Very creative. Thanks for those.
A number of people have used very creative sources for maps. Map generators from other games, satellite images, fractals, spirograph, magnetic charts, multiple layers for underworld-surface-air, ringworld, etc.
I even remember one discussion about playing on the image of a girl in a bikini.
The more creative maps dont tend to get the same play as the more mundane ones but they do add good contrast to the overall collections.