Alphabet Game
Throughout the ride, the group must identify items that begin with each letter of the alphabet in order. Once an item is spotted, anyone can shout it out. For example, "A for airplane," "B for bus stop," "C for car." Participants can get double points (if a score is taken) for alliterative items, i.e. "R for Ricky's Restaurant."
Six Degrees of Kevin Bacon
For older children/teenagers, bus companions can play "6 Degrees of Kevin Bacon." The group selects a famous actor other than Kevin Bacon. The object is to connect this actor and Kevin Bacon together within six steps using the movies they have appeared in. For example, Nicole Kidman can be connected to Kevin Bacon by the following sequence, "Kidman was in 'Days of Thunder' which also starred Tom Cruise who was in 'A Few Good Men' with Kevin Bacon" (done in 2 steps).
Scavenger Hunt
Kids of all ages, including grown-ups, enjoy scavenger hunts. This game requires preparation ahead of time in the form of a list of items with check boxes beside each one. At the start of the trip, each person is given a handout and is asked to look for the items on the list throughout the journey. Whomever gets the most items wins a prize or a simple "Congratulations." Items on the list could include a farm, a double-decker bus, hitchhikers, horses, a vehicle with more than eight wheels, etc.
Theme Song Game
One bus rider hums the tune of a familiar theme song and the others must try to guess what it is. The winner hums the next song. A variation of this is to hum popular music or commercial jingles.