Here's an interesting one someone sent me yesterday:
http://www.johnsadowski.com/big_spanish_castle.html (just follow the directions). It's not as neat as the other two, but still cool! Funny enough, I don't trust anything someone sends me that has directions for staring for any amount of time... Someone got me with one of those screaming sites once and I've never gotten over it... so when I was sent this one I turned off my volume. It's not a screamer, but if you don't trust me, just turn off your volume like I did.
Heidi