How to make "pico-hydroelectric" power - doesn't require a lot of water and generates enough power for at least one household. I was thinking something like this in-line with your water inlet system since it is already under pressure.
Shining Stars - simple tape design tree, with star garland. Washi tape would work well for this, as it wouldn't mar the wall paint. I just picked up some wide white washi tape, with "Merry Christmas" printed on it.