Gravity Flip
I got the idea for this map after playing on an upside-down map ("Topsy Turvy Hix," I believe). Sure, the upside-down map was interesting, but it wasn't very playable and it would've been a lot cooler if you could flip the whole map over if you jumped back up to the ground.
So I wrote a Perl script that randomly generated a map, then placed an inverted copy of the map above the map. I made the "sky" a one-way jump through mesh linking the two copies of the maps. This worked well enough -- when you jumped off a tall block on the right-side up copy, you'd jump through the sky mesh, and it would look as if the map turned over. But, once you were on the upside-down copy of the map, there was no way to get back down. So I modified the script to put an invisible, jumpthrough mesh directly beneath the bottom of each block on the upside-down side. The top face of this mesh had a physics driver sending you downward at a speed of -999999. This speed is enough to avoid all collision detection and sends the tank directly through everything in its path until it hits the ground. You could jump off a tall block to go up, and jump underneath a tall block to go back down. After a few more modifications, such as adding bases, and I had a finished map. One base is on the ground and the other is on the sky in the opposite corner. There are 5 shots, jumping, ricochet, and several flags. Wings and shockwave are the most powerful flags on this map, and have shot limits. Try it on my mapchange server at bzbattleground.com:9250.