"We always have a golf outing in the afternoon. In fact, we are on the 12th Birthday Outing now. We usually end up with 20-28 golfers playing a four-man scramble. This is the 2nd year that the fathers (often referred to as the Old Foxes) play our sons (naturally the Young Lions) for the Mr. D trophy (named after my Dad). Mine is a stag affair, but these things work just as well with mixed couples.
If you're having a yearly event, I recommend having a special prize for the winners. You'll find that people want to get their name on the trophy more than they want to win a prize or a bet.
I've been doing this long enough to have some statistics for you:
Average length of party - 12 hours.
How many laughs - Thousands.
Stories told - Hundreds.
Amount of fun - Too much.
The decorations help, but my friends and family make the day special. This works for me, but the key is getting your friends together in a fun, relaxed atmosphere."