Clubs are for Fun!
I am the former president and founder of the CinZroadsters, a BMW Z club. I also am a member of the GCMC Miata club and the Buckeye chapter of the BMWCCA. Generally speaking clubs have monthly meetings with attendance optional. Also there are monthly day trips in convoys over twisty back roads to local places of interest like wineries, historical sites, state parks, covered bridges etc.
Some event are national or regional where other clubs get together over a weekend. The Dragon at Deals Gap in the Smokies is a favorite. The BMW Z plant in Spartanburg SC has a big bash over the Labor Day weekend. Some club have driving schools. Sometimes car clubs decorate their cars for Fourth of July Parades and such. The CinZroadsters have a monthly event called the CinZdiners. Any member will suggest a best kept secret local restaurant (never a chain) for get togethers and socializing. Club members have cookouts and parties at their house or parks. Alway infomation is exchanged on car info.
The best thing about car clubs are the great people you meet and the friends you make. Personally I really enjoy them. When they sell enough Skys in my area I plan to form a Sky club. Carnut says he is interested when he gets his Sky.