When television shows run out of ideas, the producers resort to a "clip show" where cast members sit around saying "Remember when?" while viewers are treated to scenes from old episodes. This episode of the irreverent animated series South Park mocks that convention. As their school bus dangles precariously on a steep cliff, Eric, Kenny, Kyle, and Stan remember incidents from old shows, but anyone familiar with those old clips will notice subtle and not so subtle changes. While the boys sort-of relive old times, Mrs. Crabtree, the bus driver, enjoys a career as a stand-up comic. "City on the Edge of Forever" first aired June 17, 1998, on Comedy Central.