I'll second chromatic's suggestion. It has been my experience that going out (even to the burger joint just up the street) takes too large a bite out of the talking time. And finding a place that doesn't have background Muzak running at the 120-150db level is probably an NP-complete problem....

The lunch set-up in past years has been several pick-up-your-box-lunch lines and a large number of ten-seat tables. There has always been lots of empty table-space at the far end of the room.

I will be looking forward to meeting you.