nessus-xmlrpc is a Ruby library for the Nessus XML-RPC interface. You can use it to start, stop, pause, and resume scans. It lets you watch progress and status of scans, download reports, etc. It comes with an example command line program that shows how easy it is to interact with the Nessus scanner.
Google Authenticator Demo is an implementation of two-factor authentication using the Google Authenticator that can be used on your own site or application. It allows you to register a user name and then log in using the information provided by the Google Authenticator. It also works with OATH HOTP compliant hardware tokens.