To join...or not to join?

My son wants to join the gym. It's a great idea and I'm sure he'd get my money's worth. However, he's under 18 which means he'll have to be accompanied by an adult (me) and I'd have to pay for two memberships: mine and his. Hmm. 24Hour is having a special right now - $29.99/month per person, initiation fee's waived. BUT, I don't trust their cancellation policy (gotta finish reading it. Something sounds fishy at the end of the 6 page document) and I don't trust myself to get my money's worth :( So I'm debating between working out in my living room to exercisetv.tv, or my backyard OR signing up to workout among strangers at a gym with pushy sales people, muscle heads, and all manner of personalities. I'm perfectly fine with exercisetv.tv. I can give up, quit the workout and head directly to my own personal shower any time I want without being noticed or judged. I like that feeling. However, I can't make friends, I can't be made to feel guilty about quitting my work out prematurely or not utilizing my membership, and my son won't learn beans about boxing, which is what he wants to take a class they're offering for. And he wont have access to a range of free weights and other equipment and rock climbing and classes and an olympic size pool and a bball court and other such stuff. And neither would I. But then I'd have to drive to the gym and my living room is right there, within walking distance of my bedroom and television. I could work out in my drawls if I felt like it. That's a plus, no? I could also watch whatever television program I want without having to share the tv with a gym full of personalities.
I don't know what to do. I think I'm going to call 24hour right now and ask more questions. Their special deal ends on the 31st. Also, how typical is it to sign up for a gym on NYE? Ugh. I just KNOW they're going to be bombarded with memberships from those resolving to end their slothiness. This sloth included. It's just so uncool to be a sheep.

UPDATE:
So I spoke to a co-worker instead and found out that Costco has a sweet deal on a prepaid membership, totalling $300/person for 2 years, which translates to $12.50/month. But it's prepaid...and there are two of us :( I don't know if I should just chuck 600 bones like that. There's no refund on that deal unless you move far, far away or...die. I don't plan to do either. Hmm, decisions, decisions...