I think someone should write a textbook exchange system, partly because I
have a pile of old textbooks I want to get rid of but mostly because
it would be a really Useful Thing.
Something along the lines of a World Wide Web accessible service which
people could add books they have available, and for enquiring if a
particular book was available. Other neat stuff would be lookup available
books for a particular subject etc.
I thought about writing one two years ago in C using Xt, but quickly
abandoned it as too much work. A WWW version would probably be a few
evenings hacking Forms and CGI scripts. The scripts used for the
account application system (/usr/local/etc/httpd/cgi-bin/register I
think) could probably be used as a basis for the book exchange, although
you'd have to roll your own database back-end (reasonably easy, just use
text files and index everything by ISBN).
Although I don't have time to write and debug it myself, I would happily
give pointers and help to someone else. Anyway, mail me if you're
interested in discussing it ... or just go ahead do it.