Hysterical story I heard at Christmastime

About 3 months ago, I heard a “bit” about stories that had a Christmas theme. Tommy read a letter from a mechanic - he could barely get through it, he was laughing so hard. Anyway, the mechanic & his co workers were sick of listening to the boss brag about his great gas mileage on his new car. They added small amounts of gaqs over a period of days (weeks?) and the boss’s bragging increased to fever pitch. Then they reversed the trend and began slowly siphoning gas. The boss became more and more subdued, then flat out depressed. The boss found out what they’d been doing and made some of them work 12 hours on Christmas Eve.
I wanted to play it for my husband and son & searched on the home page and struck out. Any tips?

Home > Our Show > Browse Shows

Click “our show” at the top left of this page, then click “browse shows”, then click December 2012. You’ll have to click through each show of that month one by one to see if you can find it in the show’s description.

I definitely remember this story, both a few months back as well as many years ago, maybe three or four times actually, it’s such a great story.

Here is the letter, posted in “As Read On Cartalk”:

To hear it, you need to get it from itunes, unless you’ve been downloading podcasts. Those are accessed as George says, from “Browse Shows”: