My daughter Diana gave me this Jr. Scientist Series Mini Rhinoceros (serious assembly required). The box says it is for ages 8+. At 55 years old, I qualify.

The Mini Rhinoceros owes its design to Theo Jansen, an artist who makes giant versions of such wind-powered mechanical animals. You can see an interview with Theo Jansen here. (That link also leads to many other related videos.)

I like the fact that whichever way the wind blows, the rhinoceros always moves forward.