Working in a noisy coffeeshop provides a background level of white noise that most people find helps them to concentrate.  It certainly helps me when I need to come up with some creative ideas.

Boodler can generate this noise with noise clips.  I just discovered this, and I find that playing the summer night and wind and crow samples continuously, at a low volume level really helps me to focus.  Not too loud.  This would be neat to have playing in the corner of my apartment.  I'll play with this sometime... when I don't have a thesis due. =)

Boodler is a tool for creating soundscapes -- continuous, infinitely varying streams of sound. Boodler is designed to run in the background on a computer, maintaining whatever sound environment you desire.

Boodler is extensible, customizable, and modular. Each soundscape is a small piece of Python code -- typically less than a page. A soundscape can incorporate other soundscapes; it can combine other soundscapes, switch between them, fade them in and out. This package comes with many example soundscapes. You can use these, modify them, combine them to arbitrary levels of complexity, or write your own.

Link

Boodler: http://www.eblong.com/zarf/boodler/

Samples

Summer Night: http://www.eblong.com/zarf/boodler/samp-summernight.mp3
Wind and crows: http://www.eblong.com/zarf/boodler/samp-windcrows.mp3
Highway: http://www.eblong.com/zarf/boodler/samp-highway.mp3