Here's a cute idea from Japan: a cafe where you can only order for the person after you. So, for example, if you order a coke, and the person before you ordered a Sprite, you would get a Sprite, and the person after you a Coke. 50% Gambling, 50% Performance Art, all fun.
"Mike went up to the cafe, slapped down a couple thousand yen (~$25), and ordered a little bit of everything: some ice cream, some snacks, some candy, some drinks, a Japanese horn-of-mysterious-plenty intentionally set up as a shocking surprise for the next lucky customer. (After his order, Mike received single iced coffee.)
As we walked away from the cafe, with just the right amount of delay, we heard an extremely excited "arigato goazimasu!! thank you so much!!" yelled in our direction, from an ecstatic mom and her equally excited young son. They truly appreciated the surprise."

(Image and Article Source: cabel.name)