This is what we usually talk about before we fall asleep. Specifically, what three things in the day are each of us thankful / grateful for. Not every night, but regularly.
This, oddly, did not come about via a book / course on mindfulness but rather the question first came up after I read Sheryl Sandberg’s commencement speech at UC Bercley earlier this year (see it here). During the speech Sheryl talks very candidly about the death of her husband whilst on a family holiday and how she is working on coming up with a Plan B to her life. One of her coping mechanisms is to note down things, big and small, that she’s thankful for. She says “counting your blessings can actually increase your blessings”.
I am currently reading Tim Ferriss’ Tools of Titans (book review coming soon) where a similar approach is recommended as a meditative practice. Thinking about what one is thankful for at the end of the day seems to be very much common practice. Tim refers to it as gratitude training though in the book (ever the list-master) he suggests that you create categories of things that you are thankful for (people, work etc). Another interesting idea from the same book: 21 days without complaining.
Either way, I find it a very helpful exercise in grounding myself, reminding me to see the bigger picture and not sweat the small stuff (which I am VERY good at doing sometimes). Even on days when our car gets smashed.