Don't miss a chance to see the Cherenkov radiation effect at your local research reactor.
https://en.wikipedia.org/wiki/Cherenkov_radiation
You won't make one at home, but cloud chambers[^1] reveal individual alpha particle tracks.
There's one in the Musée des Arts et Métiers in Paris — blew my mind!
[^1]: https://en.wikipedia.org/wiki/Cloud_chamber
Edit: turns out people make these at home all the time. Sick!
If you haven't experienced a spinthariscope, I can highly recommend it. I bought one as a Christmas present for a buddy and we both enjoy its demonstration of radioactivity.
I tried the same with bananas. Got nothing.