Just Another Manic Kahn-Day is the 24th episode of season 13. It was also the last episode to air, although not considered the true ending of the series as To Sirloin with Love holds that official distinction. It was aired on May 6, 2010.
When Minh and Connie leave for the week, Minh asks Hank to keep an eye on Kahn. Hank goes with Kahn to the grocery store where Kahn is supposed to pick up his medication, but ends up ignoring his prescription. Hank talks Kahn out of the medicine, believing he doesn't need it and that Mihn may just be doping him up for having slight mood swings. Hank and Kahn start to bond over Kahn being able to modify grills and appearing super happy and upbeat- much to his usual superior mood and belittling the gang. One day, Hank and the guys go to Kahn's to check up on him when he doesn't show to build the grills. They learn that Kahn in fact suffers from manic depression, which causes him to alternate between being manic and being depressed. During this time, Grill-Stravaganza is about to occur and Kahn promises Buck Strickland to build a super, robotic grill for the event. Hank soon feels guilty for using Kahn's alternating moods to build his grill, and buys his drugs illegally from Octavio. Kahn, in a manic state, tries to say he doesn't need the medicine, showing he is getting along with the guys well thanks to being off the medicine. However, Hank convinces him that the drugs are going to help Kahn be himself, and the mood swings aren't him. Kahn takes the medication and says they take a while to kick in, stating he will either come out manic, or heavily depressed. The gang waits outside the room while he lies down to rest and wait for the medicine to kick in. He emerges from the room, declares himself manic and finishes the grill. The Grill-Stravaganza event ends up being a smashing success with Kahn's robotic grill attracting numerous customers to buy grills. The episode ends with Kahn and Hank eating a burger together cooked by the grill.
In the secondary plot of the episode, Bobby finds a Raymond J. Johnson album in Hank's closet. Bobby learns from Peggy that the album makes his father laugh- which surprises Bobby, saying that if it can make Hank laugh, that Johnson must be hilarious. Bobby listens to the famous "You can call me Ray, or you can call me J ... but you doesn't has to call me Johnson" gag, numerous times, unable to conceive why others find it funny, even playing it for Bill, Boomhauer, and Dale- who all burst into laughter, but are unable to explain why its so funny. However, after listening and studying it enough, Bobby ends up getting the humor and eventually bursting in laughter with Peggy commenting "Johnson got another one."
- This episode, and three others were broadcasted out of the season line up schedule. The series finale was broadcasted in September 2009, while this episode and others came out in May 2010.
- Tid Pao graffiti Q-Bag can be seen spray painted on the fence when the guys go get Kahn's medication from Octavio.
- When Peggy says "Johnson got another one." She is standing in front of and cooking on a non propane stove.
- The song playing when the guys visit a super-productive Kahn is "Dancing with Myself" by Billy Idol
- The title of the episode is a pun on The Bangles song "Manic Monday".
- Raymond J. Johnson Jr. was a comic persona created by Bill Saluga, who was a member of the improvisational comic troupe Ace Trucking Company which also featured Fred Willard.
- This is the last episode the Souphanousinphone family makes a major appearance, their last appearance would be in the finale as they smell the Hill's grilling and come over.
- Kahn is shown to have painted an exquisite self portrait; Boomhauer was shown to also have this talent in Naked Ambition. Interestingly, both paintings are created when each character's mental health is questioned, likely an allusion to "mad artists" like Vincent van Gogh.
- The episode title is a reference to the song " Manic Monday" by The Bangles .