Diet Coke and Mentos eruption? Works great! Put a chewed up Mentos I the cap, "stick" another Mentos to it. Carefully put the cap on. Turn bottle upside down to start reaction. Once the pressure builds up, smack the upside down bottle on concrete and it will shoot like a rocket!
Street painters like the man featured in this video clip get written off by many of us as simple tourist traps, to be avoided on your way to wherever you're going. Sometimes that might be the case, but in this unnamed artist's case, it's not – they way he paints using just his hands and a few paint-soaked rags is almost unbelievable.