Mo, I do much better sticking with an activity if it's something I enjoy, so pushups...well, I'll do them for a day, and then I "forget."
Volleyball sounds like so much fun in theory... but it would require joining a team and probably embarrassing myself terribly. I have a fear of letting down a team with my lack of athletic prowess. Last time I tried playing at a friend's picnic (probably 8 years ago?), I gave up after a short while because I was mortified at my inability to serve. Ugh. I wasn't that bad at it when I was young. There is a cool social sports group in Baltimore, but I'm afraid it will be full of 20- and 30-somethings, and I'd stick out like a middle-aged sore thumb. I suppose I could go check out one of their events to at least get an idea.
I do enjoy whacking a tennis ball around, but again, the problem is that it requires a partner to be any fun, and I don't know anyone near me who plays, much less at times when I could join them. Years ago, Jamie and I played raquetball a few times, and I wasn't bad at that -- in fact, it was really fun. But again, I need a partner! With him in TX so much, we can never get a routine down.
I'd be curious to try rock-climbing, but there's nowhere near me that has drop-in climbing walls. They're all at gyms that require monthly memberships, and I'm really not interested in that. I already have one infrequently-used gym membership! I did find one that's about 40 minutes away, and not in an area I tend to visit often.
I enjoyed kayaking, but now that we don't live on the water anymore, it's a lot of work to get in the water. Maybe I should just get a rowing machine. Then I could row at home while I binge watch Fargo or Downton Abbey.