I'm talking about particular activities, for which you can draw parallels with the specific kind of reasonning needed when solving programming problems.

Counter examples are activities that would help in almost any situation, like :

• take a shower or any other, somewhat passive activities, which are only helpful in triggering this sort of asynchronous problem solving our brain does
• exercise, because you brain simply works better when you're fit

EDIT :
It seems this question was quite misunderstood. I wasn't asking about what you can do when stuck on a problem but rather, what kind of activities you have in you spare time that you think help you, more or less directly, solving programing problems.