Risk

John rubbed his eyes and peeked over Sherlock's shoulder. "What the hell are you doing at four in the morning?"

Sherlock turned to look at him. "I'm conquering the world," he replied.

John yawned, then recognised a Risk map on the screen. "Are you seriously playing Risk online?"

Sherlock turned back at the screen and started deploying his units, "Yes, John."

John rolled his eyes and took a better look at the map. He saw only two colours.

"Which colour are you?" he asked, politely.

"I'm the green," Sherlock answered, pointing at the players bar on the top of the page. Only the green and black player names hadn't been struck.

John also read the username. "So you're 'holmecide_solver'?" he asked, stifling a giggle.

"It's a pun." Sherlock hit the 'end turn' button and leaned back against his chair.

"This 'anonymoriarty' is not who I think it is, right?"

"Whom. And yes, it's Moriarty."

"You're up in the middle of the night to play Risk with Moriarty?"

"You're stating the obvious."Sherlock replied, and then murmured an intrigued "oh" at one of Moriarty's moves.

John stared at his flatmate, still mildly astounded. "Why does it not surprise me to see you two at war with each other?"

"Actually, we formed an alliance until an hour ago. To wipe Mycroft off the board."