I was in Mensa when I was a kid. I don't know if it was just because I lived in a fairly rural area, or whether it is like this everywhere, but I was the only kid who ever attended events, and since they were at least an hour away they were always sort of a PITA. My dad, on the other hand, loved going to events because he could "pretend" to be "smart" and then shock everyone by revealing that he wasn't gifted at all.
(He
isn't gifted, but he is probably the most well-read and wildly informed person I have ever met, so it is easy for him to fool people.)
In addition to being the only kid, I may have been the only PG member in my area. I can remember that I always seemed like the smartest person at the events (but, of course, I could have been wrong).
So, in short, my advice would be to check out the group in your area thoroughly before spending the money. JMHO.
