Unless it's something simple, then I can just open vim or textmate and go to town. If it's something that I know the development scope is fairly small I may even dive in and figure things out along the way. It really depends on the project.
I can crank out a few hundred lines of code per hour but that's totally subjective. 10 lines of code in node.js do a lot more than 10 lines of code in C.
There's also the revision stage if it's a project you know you'll come back to. I generally do spend more time refactoring than the initial prototype. I would hope a lot of developers are like that.
For example, I wrote a Meebo libpurple connector in glib in about 3 hours, but I spent 2 days refining it before I could consider it useful because I had done things that were silly and not the normal way of using glib.