In episode 310, Kermit tries to hide in the box, but Statler and Waldorf throw him right off.
In episode 315, Gonzo unveils his new act, riding his motorcycle up a ramp and into Statler and Waldorf's box, first taking the precaution of chaining them to their seats. Of course, the bike doesn't even get up the ramp... the first time.
In episode 316, Janice and Floyd spend the episode in the box after Statler and Waldorf promptly leave during the opening credits. It is later revealed that they did so because they thought the guest star was Manny Kaye, the tuned clam player. (as opposed to real guest star Danny Kaye)
In episode 409, Fozzie heckles Statler and Waldorf's burlesque number, while sitting in their box.