Recently dismantled a TV and its backlighting consisted of thin cfl tubes. This gave me the material to try something I’ve been curious about for a while!
I sealed some yeast in a little section of tubing for a friend’s birthday (his last name is Baker). Kind of a shitty gift as i doubt it would survive as a keychain but I had fun making it (and its failed predecessors).
Here are the other attempts, from left to right: pepper, red and blue food coloring, yeast 
The liquid ones are giving me tiny lava lamp vibes. I would love to see then lit by an led or something. But I think they would look awesome as necklaces as well.