Episode: 9.14 (5F11) Das Bus
A Simpsons spoof on the films 'Das Boot' and 'Lord of the Flies' features a cartoon school bus:
Episode: 9.15 (5F10) The Last Temptation of Krust
"The end of this episode turns into an ad for the 'Canyonero' 4-wheel-drive vehicle. Part of the ad shows the Canyonero forcing a yellow bus titled 'Scout Troop 137' to crash into a tree." (thanks Stephen Osman)
Episode: 9.24 (5F17) Lost Our Lisa
Lisa accidentally gets on the wrong bus (22A instead of 22, driven by a characted named Larry) on her way to the museum. She finds herself lost in unfamiliar parts of Springfield. (thanks Stephen Osman)