Copping an Aptitude is the first part of the third episode in season 3 of Dexter's Laboratory, which first aired on December 7, 2001. In this episode, Dexter gets sent off to college where the students prefer to "Party now, study later". His mind then snaps from the workload.
After taking an aptitude test of some kind, Dexter's determined smart enough to attend college despite his young age. His parents drop him off at the college he's now going to school at, and Dexter's excited to finally start college. When he gets to his dorm room, he meets his new roommate, a guy named "Gabriel" (who prefers to go by "Gabe"). Gabe's excited to meet Dexter, but Dexter's disappointed to see that Gabe's a typical slacker, hippie-type college student.
Dexter wants to get a headstart on his schoolwork and gets annoyed with Gabe and their schoolmates when all they want to do is party. Gabe warns Dexter that if he goes to heavy on the studying, he's going to burn himself out, and the philosophy of him and the other students is "Party now, study later." Dexter doesn't listen, and feels that it's impossible for someone as smart as him to burn himself out on studying. One night, while trying to study, he has a hard time finding a quiet place to do his schoolwork with the other students messing around and partying.
Over the course of the semester, Dexter starts going crazy from all his studying, until he
eventually cracks under the pressure--thus proving Gabe right in that he was going to burn himself out from all the heavy-duty studying. Now Dexter's the one wanting to party while Gabe and their schoolmates need/want to study.
When Gabe and the rest of his schoolmates refuse to party with him, Dexter comes up with an idea to get the others to party with him--he turns the main square of the college into a giant hot tub, using robots to help him, heaters for the water, and a giant didgeridoo that Gabe was building as the walls for the hot tub. Dexter manages to complete the hot tub, but it ends up breaking, flooding most of the buildings and most of the snow on the campus.
At the very end of the episode, Dexter's parents have come to pick him up and take him up back to grade school, because as a result of the hot tub-incident, Dexter's been expelled from the college and can no longer attend it.