Triathlon clubs and liability

Not sure if this should be in CoJ or not. If so, I apologize.

We are looking at options for obtaining insurance for a small tri club. The club is about 6 years old and there has been a lot of turnover. I am new to the board. We're about 20 people now and hopefully growing. There is no official tax or corporate structure in place and there had been no insurance in place. I am pushing to do a basic GL coverage through USAT for $250 a year. Having no insurance at all terrifies me as we put together club rides, runs, and other activities.

We weren't planning on getting Directors and Officers insurance, as it would consume most of our budget. Thoughts?

Should we apply for 501(c)(7) status?

What about waivers? I realize they don't mean a whole lot, but every bike club ride I've been on makes us sign a waiver.

most importantly, what am I forgetting?