By almost any other form of problem solving. I started out in electronics which can provide similar challenges, but almost anything that involves solving problems to fix stuff or create new stuff will turn the trick.

For some people that is music, others may find it in flying or fishing, wood or metal working, painting or photography, computer game playing or team (physical) sports - you get the idea I'm sure. The key elements are creativity and problem solving. So long as you can find new and different problems to solve in whatever field you are engaged you should continue to take pleasure from it.