If you're not following alcademics on Instagram... well you really should be. I've been having some fun over there freezing stuff into ice balls. I'm using the same technique you've seen here on Alcademics before - a thermos and an upside-down ice ball mold.
Lately I did a couple fun ones with money, which I'd never serve to a real person because money is filthy.
I did a few with jalapenos for one event, and some with mint for another event. (Also some blue ones for it.)
And for gay pride, I made some ones with rainbow flags. I printed out and laminated some rainbow flags, and then froze those inside the ice spheres.
If you're looking for more amazing ice projects, check out the Index of Ice Experiments.
Any suggestions on other things to freeze inside clear ice balls?