The Quizbowl Resource Center

On the NAQT website, tournaments are labelled as either regular season or conference. What's the difference?

There are a few overlapping notions here, but most tournaments are one-day events, and many of them are open to anyone. Most conferences are multi-day events (often a series of weeknights of a small number of matches, and sometimes at multiple sites), and many of them are limited to a particular group of teams (such as those in a particular athletic conference).