Actually sounds rather interesting. I can see embedding various different LEDs more-or-less randomly in a pile of such marbles (maybe even some lightly colored ones, too) in an aquarium bowl as a mantle display (not talking about your wedding, here). Unless the water really adds something, could leave it dry. Or perhaps use mineral oil and use a fish tank aerator to introduce bubbles underneath the marbles.The florist said sprite bubbles adhere to the sides of the flowers. I'm not sure if we are going to do this or not but basically we put the battery pack with attached LEDs in the bottom of a vase, fill it with round clear glass marbles, add water and it gives a cool light effect.
Cost is a factor and need these to be as cheap as possible I have a ton of loose LEDs