PHP wrapper class for WHMCS API (Whmcs.Api.class.php). Currently contains the shell for every call, but only the functions used by this software are coded. This is submitted for you to use on your own projects, please contribute any code you have.
Folks interested in "open knowledge" should check out CKAN (Comprehensive Knowledge Archive Network)
CKAN is the Comprehensive Knowledge Archive Network, a registry of open knowledge packages and projects (and a few closed ones).
The University of Michigan Medical School created the Vaccine Investigation and Online Information Network (VIOLIN) because the vaccine research field lacked a web-based central repository where researchers could easily retrieve the vast amount of data underlying hundreds of years of research. Not only has VIOLIN provided the online database, the database is easily accessible via the VIOLIN API.
The tagline of the Times Open blog is "All the news that's fit to printf()", and that clever play on the paper's motto gains more credence with each new API released. In February the Times introduced the Newswire API, which "provides an up-to-the-minute stream of published items" from the paper of record, and the New York State Legislature API for tracking the political maneuverings in Albany.