I've had my eye on these solar-powered rainbow makers for some time -- they'd make great gifts for almost anyone. My kids would love this; my mom would love this; who wouldn't love this? Trouble is, whenever I've come across them, they've always seemed a little pricey. My National Geographic Christmas catalogue lists the double one for $39.99 but Amazon is offering all three styles right now for roughly half-price. Unfortunately, they don't ship to Canada.
I'm also considering getting this Uncle Milton Rainbow In My Room projector for the kids. It requires batteries and leds, though, and has slightly mixed reviews.