I noticed you're in GA (as am I.) There aren't many Datsun events HERE, but there are quite a few places you'll find us all.
A: The Mitty is held at Road Atlanta every year, it isn't Datsun specific, but it's a vintage car get together that is almost always dominated by the Japanese car scene. Quite a few Datsuns every year. You actually just missed it. B: We (Z1 Motorsports) hold an event every year in October (minus last year) called ZNationals. We used to hold it on site at the shop, but it has gotten too large and we're now doing it at Coolray Field. It isn't specifically Datsun either, but Zcar/Nissan specific. We get a very large group of Datsuns in attendance every year. If you still have your Z's that your profile say, you should bring them out. We also are hosting a track day for Znationals the day before the car show at Road Atlanta where we'll be pulling out our race cars and personal track cars with our customers, if that's your cup of-tea, Road Atlanta is a fun track to drive on. C: Caffeine and Octane: If you've never heard of it, it's at Perimeter Mall from 7am-12pm on the first Sunday of every month. It's a HUGE get together that has thousands of people across the US attend. I can't even begin to describe the event. The Georgia Z club attends every month in the summer, we've had tons of old S30's show up, 610's, 620's, 510's, everything. Nissan brought the IDX out and unveiled it for the first public showing here if I recall correctly. D: GA Vintage Class Meet: This started a few years ago. I'm 90% sure this is still going, but I don't remember when. A group of guys called The Burn Unit started this several years back at Brook Run Park south of Atlanta. It got very big for a while, mostly Datsuns.
E: Zdayz. i can't even begin to express how much fun it is. You just need to look it up and see. If you are on Facebook, make sure you're a member of the Georgia Datsun Owners page. We keep up with all local events and get togethers there.