I was thinking of starting walstad pickle jar. It would be 1g, heavily planted, and it's inhabitants would be 5-6 ghost shrimp. I would be doing daily/every other day 25% water changes or whatever is needed to keep my water levels stable.
Certainly worth it! I did a very similar thing with a 3 gallon. I was surprised to find ghost shrimp extremely entertaining - and hey, for pennies per shrimp, you've got nothing to lose! They loved algae wafer crumbles, would grab them as they fell from the surface or grab them on the floor and drag them away, sometimes bicker over their favorite pieces.