My almost-foolproof method works like this -

Drink more coffee, smoke more weed, and go read on the web until I find something that really pisses me off, something that makes me so damn angry that I am just burning to reply, then I write a refutation of whatever made me angry, but I write it on my own blog. That breaks writer's block for me, almost every time.

You just have to remember the old adage that winning an argument on the internet is like winning the Special Olympics - OK, great, you won, but you're still retarded.

If all else fails, I just write porn, the kinkier and nastier the better, until my muse wakes up from her drunken stupor.