This is mine, which I call Occasus
Spawn Room (with conveyor belts):

Top portals:

Bottom portals (teleports player to random top portal, floor kills):

Center event apparatuses which trigger 1 of 4 events (or do nothing), I've discovered it's loving impossible to hit these things when you're flying downward at a zillion miles an hour:

I plan on adding some more things, maybe random vehicles flying out of the walls and homing rockets, I only spent an hour or so on this
It's 128x128 and SEVERAL 64x64x64 cubes long