Anyone do any fun sandbox challenges?

[Hydroponics Deck]

So far I've made a rehabilitation/education zoo where I only get animals that say "rescue" on them from the market and have a big focus on staff buildings and education displays.

My second challenge/project zoo was floral desert themed and only had animals who where comfortable with very hot weather, but with the new update the floral mod I was using was broken.

Anyone else do this? I'm looking for some new ideas for my next sandbox challenge.