While many adults don't play golf, I bet every single one of us has played some miniature golf!!
What is your favorite memory of miniature golf? I love the objects you have to "shoot through" - that have a tunnel through the windmill or whatever and you have to shoot exactly through the center of them.
I think they should have miniature golf courses that are geared towards adults, with "nice" greens and a more calm, relaxing (non-screaming-kid) environment. I bet lots of adults would go for that as a Zen Golf experience