I've heard of people doing the game where you put your phones face down on the table and whoever caves at using theirs first has to buy dinner but have you ever heard of a restaurant offering a discount for not using your phone? It's not here in the US but overseas in Lebanon there's a restaurant doing just that!
The Bedivere Eatery & Tavern in Beirut, Lebanon has began offering a 10% discount on your bill if you leave your cell phone with them for the entire meal. You can read more about the story here.
I'm very guilty of being on my cell phone when at lunch or dinner with nearly everyone. I think if restaurants started offering a discount so you wouldn't be on your phone and actually talked with the people you're with that it could be a good thing. Would you do it?