The idea of a mystery is super appealing to people of many different ages! So, a mystery birthday party is certainly worthy of your consideration!
No matter what age, choose an age appropriate mystery party, and let your guests solve the clues.
You can use traced footprints to lead them to clues around the house, and give each guest a mystery pack complete with magnifying glass and other mystery pieces. The first guest to solve the crime gets a special treat!
Hire someone to be "Sherlock Holmes" Your guests would really love that! Or better still, get the parents of your guests in on the scheme, and make them a part of the big mystery!