I heard, that in MC there was a practice to use custom map seeds to generate interesting maps and recently I found out there is an option on MT too. If your seed generated an interesting/nice/whatever map, post your seed here (you can read this from debuginfo (F5)).
How to use them:
1. In minetest.conf, add line fixed_map_seed = <copied_seed>.
2. Create a new world - it will create a map with exactly that seed.
3. Revert to previous settings for you to be able to generate random maps again.
I hope that you like this idea ;).