I think the Texas committee really did an excellent job. To me, success at an NSXPO means that pretty much everyone there goes home feeling like they had the time of their lives, that it was worth the time and money to be there. I gotta believe that everyone felt that way; I certainly did.
However, each NSXPO is different. It's a product of the area where it's held, and the people who do the planning. Sometimes there is a specific activity that take place because someone on the committee has an idea and takes the ball and runs with it and makes it happen. Sometimes an activity is obvious because of the location - tours of the Honda plants in Ohio or the Realtime shop in Wisconsin were naturals.
However, the amount of time that we can spend at the event is limited. While the event is four to five days long, two or (this year) three days are for the track event. Thus we have at best a couple of days, and between activities that most people expect, like the seminars and the concours, and activities that provide "local flavor" for our location, we usually keep everyone busy for the entire time of the event. It's more often the case that we don't have enough time to do everything we'd like, than too much time and not enough to do.
Those who have never been to a particular area around NSXPO and would like to do some sightseeing, are encouraged to extend their stay afterwards. If you're interested in sticking around with other folks after the event, mention your interests here and/or on the e-mail lists when you're doing your event planning, and you're likely to find others who would be interested in the same thing - whether it's a drive to wine-tasting country, or golf, or whatever activities you happen to enjoy.