Just let it flow. Type the absolute worst sentence you can think of and keep going until something that sounds like it has legitimate potential to it pours out. Delete everything else, if you want, and play off of that. Once you dig the trench, the waterfall will flow free--you just have to find a good shovel, and those come in different shapes and sizes for every writer.

I'm a pretty cliche guy, but this is quite possibly the cheesiest thing I've ever said.

Shall I expand?