Players, staff and even some broadcasters welcomed their spouses and children onto the field, playing catch and swinging plush Astros-designed balls and bats.
The children all wore T-shirts with their dads' names and numbers on the backs.
Roy Oswalt threw pitches to 3-year-old daughter Arlee, sending some strikes by her but allowing a couple hits as well.
Carlos Lee had son Karlos and daughter Karla in attendance, and Geoff Blum's four daughters -- 3-year-old triplets Ava, Audrey and Kayla and 4-year-old Mia -- were all over Tal's Hill in center field.
Astros mascots Junction Jack and his friends joined the festivities, and the entire group got close for a family photo to end the day.
Krysten Oliphant is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.