My boss is getting married, and invited the office to a post-wedding and post-reception celebration at a restaurant. We're not invited to the actual wedding/reception, though, as it's a small event just for family and very close friends. I've never been to a post-wedding party when I wasn't at the ceremony and reception, as well. What should I expect? Should I bring a gift? Should I have money to pay for drinks? Any insight would be appreciated!