Here's a pic I already had of a chartreuse one:

The purple one Rick mentioned was all purple with silver eyes.
Mustad 3366, size 8
Bead chain eyes
Pinch of rabbit fur for the tail
Chenille body

Make sure and tie the eyes far enough back from the hook eye so you can figure-8 the chenille around the bead chain. Don't put too much rabbit in for the tail, as rabbit keeps its volume pretty well in the water, and the action of the fly is compromised a bit in my opinion. Once you get the hang of it, they're super simple to whip up.