Anything where I can hear my own thoughts. That's the hardest part for me, with a SAHM life. I often feel like I can't have my own thoughts, my own internal dialogue for lack of a better description. And as an introvert (I like people, I just recharge better when I'm by myself ), being able to focus on my own thoughts for more than 30 seconds is important to me.
I stay up late...I like the peace at night. My kids sleep in so it works out I will read a magazine out on the deck while the kids play outside together and are entertaining one another. Magazine and a cup of coffee or tea is always nice and doable in 15 minute bursts sometimes when my kids are playing.
When I need a more extensive break, a coffee shop outing, hanging out at B&N, the occasional date night w/ DH are all helpful. And crafting while DH has the kids since I can't deal w/ crafting (my own stuff) with kids around if it is anything that requires focus or attention.
eta: I get my hair cut every 5 weeks and I often arrive 15 mins early so I can chill and read a magazine for a bit to stretch my peace and quiet a little longer LOL. Whenever they apologize for running late I tell them it is blissful chilling out and reading a magazine in peace, so I really don't mind