The dates vary by location, but most areas still have a few weeks left with this freebie (FYI-It’s through the first week in August for Atlanta): 
Every Tuesday & Wednesday during the summer, participating Regal Cinemas offer a free family film festival. What does that mean for you?
On Tuesdays & Wednesdays, Regal Cinemas will play select G & PG movies. Tickets are free, and they’re distributed on a first-come, first-served basis on the day of the show. The movies start at 10:00 a.m., but if you show up right at showtime, the odds are good that you won’t get a seat.
The free family film festival runs for nine weeks in the summer. Dates & movie titles vary by location. Use the drop-down menu on Regal’s site to find a participating theatre near you.
–Jennifer Maciejewski, Atlanta on the Cheap
P.S. This deal is actually every Thursday as well.
There are always plenty of seats here, even if you are late. Be prepared that there are lots of moms with toddlers or infants that are not quiet, so for an older child this might be an interuption to the show, for the younger child feel free to leave even if the show isnt over yet! The volume is normally set lower during these shows as well, but if concerned you may need to ask your theather specifically