Wagon

Calvin's Wagon makes its debut with a run off the end of the dock on page 10 of Calvin and Hobbes .

It is interesting to note that in this scene, Calvin asks Hobbes about his views on predestination. The original Calvin (John Calvin, 16th century pastor and reformer, theological father of Presbyterianism) was a proponent of predestination. The Wagon is also on pages 12, 59, 78 (this is the strip that inspired the cover art), 123 and 127. Note that the first (cover) and last (page 127) things Calvin does are risk his life in the wagon.

Calvin's Wagon crashes even more often than Spaceman Spiff's spaceship.

On page 5 of Yukon Ho!, Calvin and Hobbes try to travel into the future by attempting warp speed in the wagon.

There's a great full page wagon scene on page 87 of Weirdos from Another Planet, and Calvin & Hobbes visit Mars in the wagon from page 94 - 99, but they forget the camera.