Line up bottles of a specific wine or champagne for guests to sign (to be opened on the 5 year, 10 year, 20 year, etc. anniversaries)

Make a polaroid camera station with a fun backdrop for guests to make a scrapbook

Sign pieces of a board game for the couple to keep (Jenga, Monopoly, etc.) 

If it's a religious wedding, place highlighters and a pen next to your religious text and have guests highlight and sign their favorite verses

Have guests fill out Mad Libs – but revolving around the couple and the wedding

Have guests fill out an “idea for a date night” card for the couples' first year of marriage