At my bakery we have a tip jar out. Normally we have two little conjoined boxes with a question of the day. For example, the question of the days could be "Lady Gaga or Katy Perry" and one box will be Gaga and one will be Perry, and they vote with their money. It's always been pretty effective and I've been doing it for about 5 years.
I went out for lunch today, and when I came back the two boxes weren't there anymore. Apparently it got knocked overand the plastic broke, so they went out and bought a fishbowl. And they taped a card to it. What did the card say?
"Give us the money, Lebowski."
I think I might leave it that way.