I remember my mom hanging prisms in the windows when I was little. The sun would shine through them and they'd cast rainbows around the house. People had them hanging from their rear-view mirrors, dangling and catching the light. No one does that anymore and I really don't understand why. I mean, they're so pretty and simple and the patterns put a smile on my face. It's hard to be in a bad mood when you're surrounded by refracted light.
When we moved into the house, one of the first things I did was order some prisms on etsy. This shop carries a wide variety of shapes and sizes at a highly affordable price. I've got them hanging in 4 different places in my house and depending on the time of day, time of year, and amount of direct sunlight, there are many spots where the rainbows brighten our space. In the kitchen I've got 5 small round crystals sewn to the bottom hem of the curtain. In the warmer months, when I keep the kitchen window open a crack at all times, a light breeze makes the rainbows dance.
Sometimes I will shake the curtain lightly to tease the cat. She turns into Ronnie James Dio on that business. Us homebodies know how to have a good time.