Years ago, I worked at Starbucks and carried with me a notebook where I wrote fairly sophisticated programs including an Oberon implementation and a core image analyzer for CMUCL.
My hand-written code is in a human intermediate language that's more hand-waving than actual code. I write the difficult parts, but all boiler-plate, syntax and other stuff are not there. I prefer either drawing pads, or ruled notebooks with very thin and very light lines. Get a spiral notebook as well; typically I only write on right hand side pages, to allow me to tear a page if I want, and to put a diagram on the left side if I need to draw something, or I get in the flow and need to spit out a few chunks of code in a spastic moment.