My DH & I just celebrated our 50th Anniversary on June 30th in Las Vegas by getting married again at the Little White Wedding Chapel. Our daughters, grand children (ages 2yrs and 4 months), & SIL. I had been driving somewhere when I heard the Faith Hill song about betting on love and going to Las Vegas to get married. We had a great time! My DH loved the idea of "re-newing" our vows, and I always wanted to see what was inside the Little White Wedding Chapel after seeing it in movies and TV for so many years. We wanted a family gathering, nothing big and expensive, just fun.
I don't know your friends but taking them out to dinner and celebrating the occasion with a card or even a bouquet of flowers would be fun for you all.