Then one site to check is fsi-language-courses.com. These are US Foreign Services courses in the public domain. Many have student books (PDF facsimile) and audio. Here's what the site intro says:

Welcome to fsi-language-courses.com, the home for language courses developed by the Foreign Service Institute. These courses were developed by the United States government and are in the public domain.

This site is dedicated to making these language courses freely available in an electronic format. This site is not affiliated in any way with any government entity; it is an independent effort to foster the learning of worldwide languages. Courses here are made available through the private efforts of individuals who are donating their time and resources to help others.

So, grab your glottal stops and head over to try to learn Arabic, or perhaps some German, or perhaps fool around with some modern Greek.