Film photography. With smartphones having taken over the roll of point and shoots and covering the majority of people's photography needs, it's quite a different experience breaking out a half century old camera. Everything is more tactile, your shots are finite, and the result is a 100% determined by your decisions. Different films produce different results, and if you get into developing your own film you get to play mad chemist in the bathroom.
There's a learning curve, but if you're already into photography and understand the basics it's really not that hard. Labs still exist to develop for you if you'd rather not go down that rabbit hole. The results may surprise you!
It's like the odd time I drive an automatic after decades with a manual ... always mashing the floor and popping it in neutral by accident.