Are you a Metasploit user, and want to hack stuff (that you have permission to hack) just like in the movies? The quickest way to get started is to download the Metasploit binary installer. This will give you access to all Metasploit editions: the free, open source Metasploit Framework, the free Metasploit Community edition, and a free trial of Metasploit Pro.
If you're an exploit developer, you will want to review our Guidelines for Accepting Modules and Enhancements to find out what all we expect when we see pull requests for new Metasploit modules. No idea what you should start working on? Check out the guidelines for contributing to Metasploit, and dive in to Setting Up a Metasploit Development Environment.