I've been riding a bicycle for a little over a year and really enjoy it. About once a week I'll ride 4-5 miles to a coffee shop and work from there in the afternoons. Otherwise, I do small errands on my bike, like picking up groceries, picking up take-out food, or checking out a book from the library. The trips are short and my area is pretty flat, so it's light and pleasant exercise. I also save some gas money by not driving my car so much, and it's just so nice to be outside and feeling the wind go by me.
One aspect I'm enjoying more than I imagined is tinkering with my bicycle. I think that tickles the nerdier part of my personality: comparing different ways to carry cargo, adjusting various things to achieve more comfort, light maintenance like inflating tires and lubing the chain, etc. It's fun.
Historically, a lot of my hobbies involved me sitting in front of a screen (movies, video games, recording music, etc). Now my work is more screen oriented than ever, and I found such hobbies felt a little too much like my work, so I needed to find something very different. Biking has been good for me.