- pink bubblegum seen in the hallway at school;
- one girl's pink tongue;
- the red hearts of the cards in the bridge hand;
- the subtle green of the car in front of the diner;
- the jukebox in the diner becomes multicolored the guy in front of the jukebox combs his hair with a yellow comb Jennifer's red cherry on her shake in the diner;
- the pink cherry blossoms reflected in the side mirror of the car;
- the subtle green of the grass at Lover's Lane before it turns completely colorized.
In the scene where Bud is driving Margaret to Lover's Lane, he is driving a white convertible, and a beautiful, period-appropriate song is playing in the background. That car? A 1949 Buick Roadmaster. The song? "At Last," by Etta James.
The same car driven cross-country by Tom Cruise and Dustin Hoffman in Rain Man, and the same song Cruise and Hoffman dance to in a very touching scene near the end of the movie.
Maybe a hidden homage, maybe not. But if not, one of the coolest unintentional movie references ever.