I like walking, personally. It's something I can do at my own pace (unless there's people behind me on the sidewalk) and something that I can easily zone out while doing. I don't think I could zone out while biking because I would probably crash and die a painful death. I also like hiking, nature is a great stress reliever for me
Gotta agree with the other people saying bodyweight, it's so cool because you feel like you're unlocking your potential. Being able to do hand stands, flagstaffs and the like is a really awesome feeling. Plus IMO you look way more ripped than just doing free weights at the gym. You develop muscles you never knew you had.
Lifting and yoga I also do a light bodyweight workout right after waking up to get the blooding flowing and warm up my old joints it makes all the difference, also swimming