I used to have these cheap, waterproof light ball things, that could be either red, green, blue, or a slow transition between all three. They were designed for use in a pool, but I got them for my shower.

They were absolutely perfect. If I was having trouble sleeping and decided to take a shower (which sometimes help me sleep), I could keep my night vision intact by setting the light balls to red. They provided plenty of light for me.

I moved houses since then, however, and haven’t seen them in years. I’m going to have to look around pool toy sections soon, see if I can find something else like them.