biking. its fun and has health (both mental and physical) benefits.
it was tough first few times but now I cant wait any longer than 2 days to jump on my bike for an hour long ride.
I read somewhere that its not recommended to bike on roads busy with cars because the pores in lungs open up while biking and all that polution goes straight in.
I noticed some people are biking on dirt trails parallel to the paved trail because the paved one is too crowded with people, their children and childrens strollers and all that.