Many volunteers who donate their time to museums or other cultural institutions do so for access to the facility in addition to their interest in the mission of the facility. When it came time to organize a recognition for volunteers at the science center, it was assumed we'd have some sort of recognition dinner.
I felt the best gift we could give our volunteers was a free evening for them and their families in our great facility. The bonus was seeing how easy it was to get staff to volunteer that evening so the volunteers could party. We usually offered some sort of light food in the cafe and had every bit of the center open and free to our volunteers and their friends and families. We always had some sort of food related thank you theme, like Pizza and cake, "Volunteers, thanks for sharing a slice of your time" an ice cream social became, 'OMSI has the scoop on the best volunteers!' Staff truly enjoyed helping out, with the food serving positions usually the job everyone wanted.
The added bonus was hearing staff say the next day how much they enjoyed meeting all the volunteers and seeing how much these people loved our science center. The staff, especially those who didn't work closely with our volunteers, were especially struck by how much our volunteers treasured and valued what they did for us, and how proud they were to "show off" for their families. I almost think the staff looked forward to this yearly event more than some of the volunteers, it was a great way to build camaraderie and a real morale booster. Now, at a new science center, I'm looking forward to continuing this tradition with a new group of volunteers and staff.