"Homer and Lisa Exchange Cross Words" is the sixth episode of Season 20. It aired on November 16, 2008. The episode was written by Tim Long and directed by Michael Polcino. Merl Reagle and Will Shortz guest starred.
Lisa discovers she has an impressive knack for solving crossword puzzles and she enters in a city-wide crossword tournament. Feelings are hurt though when Homer bets against Lisa in the championship match.
Bart and Lisa sell lemonades but no one came so Bart put a dollar in the jar and immediately people came to buy lemonade from them. Homer then comes home from walking the dog and ask Bart for a lemonade which was to be put on his tab. This was refused by Bart who had a cash only rule making Homer need to go to Moe's but needed to borrow Lisa's bike because his car wasn't working. At Moe's he saw Mrs. Krabappel try to break up with Skinner but couldn't so offered a beer to whoever who could do it for her. Homer takes her up on the offer breaking her up with Skinner and with Carl commenting that Skinner felt better after the break-up. Lenny then asks Homer to break up his him and his girlfriend, Dorin, to whom was referred by Moe as having cheated on Carl with everyone except himself. Homer then does this but starts off the conversation by saying Lenny's dead but then changes this when Dorin sees past his lie.
Lisa and Bart's lemonade stand is now destroyed by the Blue-haired lawyer due to their lack of a vendor license. Bart then tries to bribe him with 35 cents but does so in vain. Lisa and Bart then go to get a vendor license but the man there is doing a crossword so Lisa decides to complete it for him and tells him to give everyone licenses.
Grady then asks Homer to help him break up from his boyfriend Julio. Lisa becomes obsessed with crossword puzzles after she helped the man finish one at the vendors license. Homer then goes to a hardcore gay club and breaks up Julio and Grady's relationship before breaking up everyone's else's in the club's relationship. Homer then breaks up the relationship of Miss.Hoover and an unnamed man, another man who was looking to get married and Snake and Grady.
Then after talking to superintendent Chalmers Lisa enters a crossword competition and begins winning rapidly. Meanwhile, Homer under the advice of Marge and after a nightmare being chased by antique furniture, ghosts of people he broke up and the ghost of unborn babies stops his break-up business. He then finds a pub where the competition is being held and bets all of his money on his daughter using the money he got from the break-up business charging everyone 100 dollars. In the last match, he bets against her and wins because Gil Gunderson tricks her into picking up his glasses, stalling her so he can win. Later, Lisa finds out that Homer is betting on her, and she becomes angry with him, and changes her last name to Marge's maiden name, Bouvier. Homer, feeling bad, and trying to get Lisa to forgive, gathers the crossword editors of The New York Times, Shortz and Merl Reagle to make an issue, with a message on the diagonal grid from right to left and another reading to first letter of each clue. Lisa then forgives Homer and hugs him.