We plan to visit May 10th and that date is grayed out on your calendar. Are tickets set aside for those people who want to pick up timed passes in person for same day visit?

It's free but call or ahead

Hi Michelle, After checking the site, it seems that on May 10th, you can only get in person same day tickets, although I cannot be sure. If you were to reserve them online they only cost a dollar, but in person tickets are free. The website is a bit cryptic, but just to be safe I personally would suggest figuring out another date that would work for you, just incase there's some large group or they're closed.