Making new friends as a grown-up is weird

Tomorrow night Andy and I are going to dinner at the home of some new friends. We met them through our foster classes and they were the closest in age to us, and they seemed like decent folks. We noticed them chuckling at the same kinds of things we chuckled at. We learned that the girl (lady? woman? the female half of the couple, anyway) teaches at my old high school, and the dude works at the same company as my brother (no, they don't know each other). We ran into them in a bookstore and got to meet their adorable son, who was busy trying to fit all of his chubby little baby fist into his own mouth.

So we friended each other on the Facebook, and have sort of kept in touch that way. The girl messaged me a week ago to ask me a question about our CSA (they had a share in a different farm last year and it sucked, so they're going with our guys this year!) and suggested doing dinner! Hooray!

We're doing it at their house, so their now-toddling son doesn't get up to any shenanigans. They're making spaghetti and meatballs and we're bringing salad and wine. I really hope it's a fun, relaxing evening with new friends who will someday be old friends.

So, like, do we bring some sort of hostess gift besides the wine? How long are we supposed to hang out after we finish eating? We don't have comfortable routines to fall back on!