US-based non-enterprise programming conferences?

What are some US-based conferences for people interested in software or computer science?

- not focused on enterprise and big business (at least not as a primary focus)

- mostly focused on topics in software, computer science, and programming languages (and not computer hardware, hardware makers/hackers, and so on)

- preferably with a strong component of bringing people together in person to share some kind of passion, project, or personal interest

Suggestions?