Meet the Propaniacs is an episode of King of the Hill.
Bobby wants to attend a comedy summer camp, but Hank vetoes the idea and arranges for him to work at Strickland Propane instead. When a grill shortage occurs at a big sales event and Dale incites the crowd to anger, a quick-thinking Bobby recruits Joe Jack and uses propane-themed comedy to appease the crowd, and Hank comes to appreciate his son's talent for making people laugh. As a result of Bobby's success in averting the potential crisis, Buck Strickland proposes sending Bobby and Joe Jack to the company's other branches to boost sagging sales and employee morale. Thus the Propaniacs, consisting of Bobby, Luanne, Joe Jack, and Donna, are formed, and with Dale's musical accompaniment they visit each branch of Strickland Propane to perform a series of short improvisational comedy routines related to propane and propane accessories.
Eventually the Propaniacs are invited by Charlie Fortner, the president of the Texas Association of Propane Dealers, to perform at a regional propane convention. While discussing the troupe's routine for the performance, Hank and Bobby get the idea to invite Fortner up onstage during one of the acts, choosing the 'Gas Cop' sketch (during which Joe Jack roleplays a cop and 'arrests' Bobby; though for the purposes of the convention's performance, Joe Jack would 'arrest' Fortner instead). However, Joe Jack becomes anxious about meeting such a high-profile propane personality, and, sneaking off, retreats into drink. At the start of the show, Joe Jack is nowhere to be found, and the others are forced to start the performance without him. Hank takes Joe Jack's place as the 'Gas Cop' and calls Fortner onstage, but Fortner declines. As Hank drags the protesting Fortner onstage, Joe Jack wanders out, completely drunk and wearing the diaper for his baby costume from another sketch. As he stumbles his way over to Hank and Fortner, the diaper falls off, causing him to inadvertently flash the audience. Covering himself, Joe Jack drunkenly asks a horrified Fortner for another diaper, and Hank, still trying to carry out the sketch by frisking Fortner, and accusing Fortner of stealing a diaper, discovers to his horror in turn that Fortner's self-consciousness stems from his own use of adult diapers.
Despite Hank's truthful insistence that the incident was unintentional, an outraged Fortner forbids the Propaniacs from further performing at conventions or propane outlets. Peggy books the troupe at the Arlen Mall, safely out of Fortner's jurisdiction; even though the troupe's propane-specific humor proves a bit too topical for a mainstream audience, Hank still enjoys watching Bobby and the others put on the show.
Hank: Blackout! (laughs)