A Jewish father has two kids who want to sell lemonade on the street 
corner for 15 cents a glass.  He figures he'll spend about 3 bucks on the 
ingredients, the kids will sell maybe 10 glasses and then drink the rest 
and get stomach aches.  His eventual response:

   "Go stand on the corner for two hours and come back, I'll give
you two dollars.  Everybody wins."