We’re of the school of thought that a joke requiring explanation is a joke failed. We also spend a lot of time explaining our jokes. The estimable Adam Sternbergh, on the other hand, we always thought tossed off bons mots and witticisms of such perfection they required no explanation. Apparently, however, we were wrong. A friend pointed us the other day to Behind the Approval Matrix, a new-this-week blog that, well, explains Adam’s Approval Matrix jokes. Didn’t get his reference this week to “That bizarre Elvis Mitchell cameo on Entourage,” to pick a random example? Behind the Approval Matrix explains: “According to his Wikipedia entry Elvis Mitchell is a former film critic for the Times, and is one of the most well-known African-American critics in the United States. On Entourage he interviewed Vince, E, and Walsh about the genius behind Medellin.” Now you know.