swimming, where you actually do lengths (you may not like swimming, I am talking about if you enjoy it rather than trying to foist virtuous exercise upon you)
going to interesting places with lots of steps and wandering about looking at things for exactly as long as you like
Visiting friends and relations (especially those who are likely to make a fuss of you, if you have any). Arriving, going into the house and being offered tea (which you can drink in your own time and put on a table with no fear), catching up in a nice long interesting conversation, maybe having a long dinner and going to bed in their spare room without having an agonising night trying to get the baby to sleep somewhere strange, horribly aware the whole house is being disturbed. Lie in and big lazy breakfast with more interesting conversation, or the newspapers if you prefer. A walk or a film or a pub lunch or whatever. Leaving whenever you like instead of being forced out the door by constant whining and howling and grizzling because only getting in the car will put your stressed out and beyond-it baby to sleep and you just can't inflict this misery on your hosts any longer, forgetting half your stuff, feeling icky because you haven't showered because you were trying to stop the baby driving the whole house mad, getting home frazzled and desperate, feeling like you hardly saw your friends and thinking, what on earth was the point of that?
creative or crafty stuff, if you like it. Pick a project where you will have time to complete it and if possible make it something that you will be able to look at often, after the baby comes, to remind you who you are, and what you could do, and what you will be able to do again