"Make Room for Lisa" is the fifteenth episode of Season 10.
Lisa experiences stress when forced to temporarily share a room with Bart. Meanwhile, Marge discovers the joys of eavesdropping on cellular telephone calls and becomes obsessed with the personal dramas of complete strangers.
Homer must take the kids on a family outing in order to bond with them, and unfortunately for him Lisa gets to choose as Bart traded his turn for her dessert, which he did again when Homer punished him with no desert. They visit a national treasure museum sponsored by a cell phone company, Omnitouch. While there, Homer accidentally wrecks the Bill of Rights and is forced to repay his debts. He does so by letting the Omnitouch representative build a cell phone tower on their house. Lisa comes home one day from to school to find that her room is gone and replaced with several machines to help power the tower. She gets really upset with Homer.
Now that her room is gone, Lisa is forced to stay in Bart's room, where he purposely drives her crazy. After a while Lisa starts to get severe stomach aches caused by stress. Dr. Hibbert says he can give her harsh antacids, but feels that herbal tea might suit Lisa better. Lisa agrees until Homer buts in saying he won't let Lisa near the stuff and demands the antacids. After finally having enough of her father belittling everything she likes and believes, Lisa snaps at her father, claiming that just because he thinks what she likes is stupid and boring doesn't make that true. Seeing this upset her father she calms down and tells him that they're just too different, and they'll eventually grow apart. To get her cooled down, they visit a store run by a "hippie lady", who sells all different types of soothing items. She gives them some time in some isolation containers that will allow them to think. Lisa goes on a mental journey where she sees herself in the form of Snowball II and Homer where she realises that Homer really does try to be a good father and takes her lots of places he hates. Homer, however, is not thinking and his container is taken away by repo men who aren't willing to wait for the hippie lady's lease to expire. His container falls off the truck and the Flanders find it, believe it's a coffin and bury it. His breaks though the ground and ends up in the ocean and washes up on shore, where Ralph Wiggum reports it to his dad. They bring it back to the store where they both get out and reunite. Lisa and Homer then go to the monster truck rally to spend time together.
Meanwhile, Marge starts hearing cell phone conversations over the baby monitor and starts using it for her own gossip gain. Bart and Milhouse decide to teach her a lesson by pretending to be robbers about to hide out in the house. When Milhouse opens the door, Marge smashes the baby monitor over his head. Having learned her lesson, she and Bart drag Milhouse's unconscious body inside and claim that "Bart hit him".