I go to every restaurant in a geographical area. Right now I'm going through all of the City Heights district of San Diego: 65 down, about 25 to go...

I've also done Del Mar (110 restaurants), Downtown SD (around 80 before I stopped) and 30th Street (maybe 35 or so?).

Oh, and I've been in a group for the last 10 years that goes out to eat at a new restaurant every couple months.