According to Mike Greenberg and Mike Golic (of Mike & Mike In The Morning on ESPN), this came about because Jon was starting to play Wanted and said he'd donate $50,000 if Belichick and Weis joined him on the song . . . so, of course, they did! Mike & Mike didn't give any additional details about the show, but they were both raving about how cool it was to be at this event where Jon was performing for such a small group. Evidently they're both big fans.