Magical Girl Day, formerly known as International Sailor Moon Day, is a convention coming up on August 5th at the Crowne Plaza Galleria in Houston, Texas.
Tickets are $18 if preordered and $20 at the door. Looks like the event focuses mostly on cosplaying and pop groups. Check out the website for information.
I believe this is the first one. We’ll see if they manage to make it an annual event. It appears to be modest in size and scope, but like all such things, will grow if successful.