This refers to playing the game "RuneScape" created by Jagex. When someone is going to spend time playing on Runescape, or indeed is already playing on the game they are "Runeing it up"
"So George, are you going to Rune It Up today!?"
"It's time to rune it up"
"i'm gonna fucking "rune it up" all weekend!"
"It's time to rune it up"
"i'm gonna fucking "rune it up" all weekend!"
by swimace September 10, 2007