Aidan, Karl, Martin,
Thank you guys so much for all the ideas. I'm definitely going to try aluminum foil and mylar. I'll also play with making small holes in them and see how that works. I went to a Chinese store today and found some nice crystal balls with plenty of angles. I used a small battery lamp to test them in a dark corner and it seems nice, only very hard to control and too shaky, since the crystal is small and in my hand. I'm thinking the hanging crystal ornaments from a ceiling lamp would be a good one as well. I'll keep you guys posted with the results...