A web interface to an audio tool is really only useful when running
locally; plus, IIRC, there's already a Borges-based MP3 player
interface written in Ruby.

I think the business card tool sounds pretty good -- allow a user to
edit their contact info, upload a small graphic as a logo, select one
of a few pre-designed templates, and then generate the card as SVG or
PDF.

-- 
Lennon
rcoder.net