Pi Day celebrates one of the world's most popular mathematical constants.
Brad's Deals Editor Jim,
Today only, get 31.4% off select items during this Pi Day sale at ThinkGeek. Shipping is free on orders over $75, otherwise it adds $8.95. Pi Day celebrates one of the world's most popular mathematical constants. The promotion includes this Pi By Numbers T-Shirt, which lists at $19.99. It falls to $13.71 during the sale. This Mathematics Canvas Crossbody Purse falls from $24.99 to $17.14, and this Math 20oz Ceramic Mug drops from $12.99 to $8.91. Those are the best prices we can find anywhere, and the sale ends tonight. Sales tax is charged in most states.