Most hobbies cost a lot, few two people in the same house and sleeping together will enjoy with each other.
Reading, writing, painting, make art or furniture for around, photography, walking, camping, dancing.
Heck got talking to an 84 year old woman offering to sit on my lap and her husband, they loved singing karaoke it seems.
I find friends are a good way to pass time, offline when free, online if not. Find a home go wild and have fun.
Charity or community projects.
An interest in history and museums.... ??
I still paint and collect miniatures because I'm a big kid.