Open Bar is the only way to go.

I've been to 3 weddings. the first was a family friend, I was 13, so I only drank like 2 beers my dad gave me. The second was my cousin on my dad's side, I was 16, was able to drink quite a lot, before they figured out I was underage, and had a great time. The last was at my pro-golfer cousin(Roland Thatcher), on my mom's side, I was 17, open bar and they didn't care I was underage. I don't remember much other than the dinner, and having a blast with all the people I wasn't really related to, and only a few of whom I had known previously.