ABC is promoting 500 Questions as a seven night event starting May 20,. cutting down two nights from what was originally stated.
May simply be a case of opting not to air episodes Friday and Saturday, given how low ratings are for regularly-programmed shows both nights.
The Futon Critic lists no new episodes on Saturday or Sunday - not too surprising, considering that it's Memorial Day weekend.
Saturday: repeats of episode 1, and 2 hours of
In An InstantSunday: repeats of
America's Funniest Home Videos, 500 Questions episode 3, a couple of
Fresh Off the Boat, and
Castle - this competes against a NASCAR race on Fox and the National Memorial Day Concert on PBS
EDIT: It also lists that the two Thursday episodes will be two hours each, so the total running time will be 9 hours as originally planned