There were a lot of white boards in Rodney's labs. They were covered in different handwriting in at least seven colors of erasable markers, the writing dominated by Rodney's bold and weirdly loopy script. Rodney mostly had written equations, but there was the occasional insult with an arrow pointing to whatever he'd found offensive, some numbers that had been circled so furiously that it looked like they were surrounded by a green hurricane, and a third of one board was taken up by an enormous question mark.
One of these white boards wasn't like the others. Only two people ever wrote on it; John Sheppard in black, and Rodney McKay in blue, green, brown, red, and on one memorable occasion, purple.
It was the scoreboard: for chess, racing, video games, computer games, and the handful of bets where one of them had emerged as a clear victor. Rodney was examining that board now. John was sitting on top of a lab bench with his arms crossed, eyes raised to the ceiling.
"I'm winning," Rodney said slowly. Then, "I'm winning! Ha! In your face!"
Rodney raised his arms, and then scooted around the lab in a victory dance, wearing a silly smirk and humming something that sounded suspiciously like 'Eye of the Tiger'.
John let him have his moment. He was only three moves away from checkmate in their current chess match, and it was his turn to choose the next Xbox game, so naturally he was going to pick something that Rodney had no chance of winning.
When Rodney's dance went on a little too long, John said, "Keep that up, and I'll forget why I have sex with you."
Rodney stopped dancing and sighed. "You're a sore loser, Sheppard."
John snorted. "Heh."
"You're such a dork," Rodney said happily.