Competition! I frequent the NaNoWriMo irc. During November, I'm never hurting for people to have word wars with. I'm competitive, and having people writing alongside me with a set time frame is GREAT for getting stuff down. And no matter how long you're wanting to war for, there's someone to go alongside you. I've seen wars anywhere from a minute and a half on up to two hours. I can thank word wars for the majority of what I get written.