1 Million Cups is a fantastic community to get involved with. 1MC generally hosts two pitches each week (Wednesdays at 9am), after which attendees in the audience offer their input, suggestions, and feedback. It's a great way for entrepreneurs to practice their pitches in a low-key environment and among peers. The application process is super simple and you'll probably get contacted within a day to schedule your pitch.
Based on the notion that entrepreneurs discover solutions and network over a million cups of coffee, the Kauffman Foundation developed 1 Million Cups - a free program designed to educate, engage, and connect entrepreneurs with their communities.