All online vouchers are gone, but there will be some available for people who walk up.
Several of the team's star players and legends are expected to be there to give fan autographs, including Jose Altuve, Alex Bregman, Carlos Correa, Jeff Bagwell, Lance McCullers Jr., Art Howe, George Springer, Justin Verlander, Tony Kemp and Tyler White.
You can see the full list of everyone scheduled to attend on the Houston Astros website.
There will also be a Q-and-A session, and fans will get their first look at the plaques that will be placed in the new Astros Hall of Fame.
The team announced the Hall of Fame earlier this week. It will be a physical hall constructed beyond left field at Minute Maid Park.
It's set to open when the team hosts the Pittsburgh Pirates for an exhibition series March 25-26.
The Hall of Fame inaugural inductees will include Nolan Ryan, Craig Biggio, Bagwell, Larry Dierker and Jose Cruz.
READ MORE: Houston Astros Hall of Fame's inaugural class boasts household names
While walking around the fest, don't forget to try samples of the new Crawford Bock beer. The brew is a collaboration between Karbach Brewery and the Astros.
The event runs from 11 a.m. - 4 p.m., and you'll definitely want to stick around.
At 3 p.m., Bregman plans to make a special announcement.