We like the idea behind this little book we spotted at Ecohome Improvement in Berkeley. Rather than throwing away paint that didn't come out the right color, they paint a little swatch in a book of "limited-edition, custom colors." We're thinking the idea could be adapted for use at home, too...

...but not to sell paint, of course. We've always kept a file of paint chips, but a little book full of the paint that's actually on our walls might be more useful in this day of computer color matching.