It's worth dusting this off: a simple, accurate equation that decides to the penny how much you should spend on anyone's gift this holiday season. Get cracking you slacker.

I wrote this for the Science Channel, but basically it's a framework that allows you to split any defined, limited resource according to your priorities. Actually, a friend of mine runs the Cornell Outdoor Education program and after seeing the Science Channel bit, emailed to say he'd used the same strategy to split the yearly operating budget. (Independent of my equation—actually, the dude's a genius. Much, much smarter than I'll ever be. A laser microscopy PhD before taking extended hiatus to run C.O.E.) You could use a similar equation to split your weekend hours or recreation budget, etc. What else? I'd be interested to know.

Here's how it works:

•  First, what's your TOTAL holiday gift-buying budget?
•  Now list all the people you have to buy gifts for.
•  Rank the importance of each of these people: write a number 1-10 with 10 being important in front of each person's name.
•  Now add all these ranks: if you have people ranked 10, 6, 5, 3, 3, 3, 2, 2, 2, 2, 1, your total would be 39.
•  Set up an equation with this total (times a variable) equal to your budget—for me: 39x=$500
•  Solve: x=$12.82
•  Multiply x back into your priorities list: on someone ranked "10" you spend 10x or $128.20. On someone ranked 6 you spend 6x or $76.92.
•  Evil laugh, for you have solved the age-old mystery of gift buying.

BTW--the unwitting dupe in the video is actually a ringer: Christiana'sa friend of mine. And the toy store is the extremely cool, independent, small-town Serendipity Toys in Ojai, California, run by a guy with a Berkeley engineering degree. You should see their toy train set ups.

No, no: no need to thank me in the comments section. Instead, for all the people on your list on whom you're planning to spend $12.82, consider picking up a copy of my book Brain Candy: Science, Paradoxes, Puzzles, Logic and Illogic to Nourish Your Neurons. At this point, consider rush delivery.