In honor of National Engineers Week (stolen from SSC) :
A grocer wants to expose his oranges neatly for sale. Doing this he discovers that one orange is left over when he places them in groups of three. The same thing happens when he tries to place them in groups of 5, 7, or 9 oranges. Only when he makes groups of 11 oranges, they fit exactly. What is the minimum number of oranges that the grocer has?