Jimbo is born to be wild and bad to the bone (in his own mind, at least) when he gets a hold of a dirtbike.
Springfield Elementary is offering a dirtbike as the first-place prize for their Arts and Crafts Fair (because they want all the kids to attend and not just the art nerds). Jimbo, Dolph, and Kearney eye up the dirtbike, but are told by Principal Skinner that they'll never win it since they they don't know how to express themselves creatively. The bullies decide to retaliate by stealing the dirtbike.
A bit of hot-wiring and pants-pulling later, Jimbo rides the dirtbike through the school to cause some mayhem. He wrecks Martin's toothpick model of the mothership from Battlefield: Earth and gives Martin himself a mobile wedgie, then takes Bart's exhibit of lit firecrackers and throws them into Lisa's Jazz-celebrating cake. Jimbo then rides out of the school and continues to cause mayhem by swiping Homer's Krusty Burger meal and a Squishee from Apu. However, his theft of a donut from Chief Wiggum's hand gets him into a police chase. Jimbo flees to Shelbyville, but his joyride ends as soon as he crosses the city line when the dirtbike runs out of gas, and Wiggum confiscates the dirtbike before driving Jimbo back into Springfield.
Two weeks later, Principal Skinner compliments Jimbo on being a model student and claims that it was his authority that managed to turn the bully around. Jimbo proves otherwise to Dolph and Kearney by demonstrating his knowledge on the table of measurements as he pours sugar into the gas tank of Skinner's car.