We just did this in August for DH's 40ith. We were supposed to go to Disney...booked and paid for. I got sick. I was in the hospital and came out on August 5th. I decided to try to have a birthday celebration for him. I got some help from friends, ordered food, decorated a friend's house in a Red Sox theme, and emailed invites to about 85 people. 9 days later, there were 75 people decked out in their best Sox gear yelling surprise. It was great! As it turns out, we went to Disney for my birthday in December. What a change in events! Good luck!