The double R’s everywhere. Here’s a snapshot of the Roc Boys setting up for Eminem and Jay-Z’s performance tonight on The Late Show With David Letterman. We see ya, Guru. Instead of rocking the marquee, the rappers have taken their act to the roof. The performance airs on Friday. Oh yeah, tickets for September‘s concerts go on sale Friday too. Remember: Detroit 9/2 and NY 9/13. Recovery in stores today!