Dean could listen to the same 20 tapes on repeat for a month straight without thinking twice about it; Sam, on the other hand, had learned from experience that three days was enough to break him. And Dean was persnickety enough about his music that radio was very hit-or-miss—most stations couldn’t make it past the first commercial break before getting switched off. Hence Sam’s playbook of alternate tactics for preserving his sanity when stuck on the more meandering cross-country drives.
Reading with headphones on had saved him more than once, but always left him feeling vaguely guilty, like he was snubbing Dean (not that Dean usually seemed to care—or even notice, sometimes). Nostalgia about their childhood was a bit of a minefield, but often happened of its own accord if they found themselves driving through familiar territory. There was also the ever-popular game of making wild speculations about the case, based solely on the news reports—Dean, Sam could admit, had turned this into an art form and seemed to take equal glee in leaving Sam either breathless from laughter or struggling to keep his lunch down.
Getting Dean to riff on pop culture could go a long way and was at times truly fascinating—Sam would never have guessed that Dean had watched Truly, Madly, Deeply even once, let along often enough to memorize entire scenes. (“Research,” Dean claimed, completely straight-faced. “There’s ghosts in it, man—that totally counts. And Snape—though he’s kind of a wet nelly in the movies.” “Do you even know what that means?” Sam demanded, leaving aside the issue of Dean’s familiarity with Harry Potter, from which things progressed into a full-blown but cheerful squabble over slang.) Of course, if allowed to run on log enough, Dean usually wound up giving a scathing critique of the most recent remake/reboot/sequel. Sometimes Sam would play devil's advocate just to really get him going; sometimes Sam was left wondering how the heck his brother managed to collect and retain so much movie & television trivia; sometimes Sam couldn't help but join in (because really, what was up with all the shitty live-action remakes of kiddie cartoons?).
From time to time, when he was feeling really, really bored (or nostalgic), Sam would haul out the battered dictionary that still lived underneath the seat and read aloud the weirdest words just to hear what Dean could come up with in response. He was an apparently endless fount of invention and unexpected facts: on separate occasions, 'kumquat' had yielded both "I dunno--sounds like a yoga pose", and "Isn't that like a Asian lucky charm or something?"
But sometimes, on golden afternoons, when the roads were empty and the Impala's engine maybe almost really did sing, Sam would just sit and watch his brother in the shifting sunlight, the road and world spinning away beneath them like an endless ball of string, leading them on into the days to come.
It was (he sometimes let himself think) perhaps what 'home' meant.