The following instructable details the process of building a lighted fabric jellyfish. While we created these as a part of an automata aquarium, it may be useful in your other projects as well.
These jellyfish were controlled by a small arduiono using the example blinking method found on the arduino examples website
-Slightly Sheer Fabric
about 1/4 yard
-Thread to Match the Fabric
-Quilters Batting (any kind)
-Sewing Machine (or needle to hand sew)