Are you flying in? Getting up early? My kids don't sleep on the plane (too keyed up) and are too excited to nap once we get in (they are 4 and 5) so with UPHs we might as well hit the parks. But we plan for an early night. This last trip we arrived at the hotel about the same time you are (we were staying at BWV) we dropped off our luggage, walked into Epcot and had a late lunch at the Biergarten (we were all starving from travel). Then we rode a few rides in Epcot (Journey into Imagination and Spaceship Earth) before heading back for an early bedtime (early being the kids were asleep around 7:00. The grown ups sat on the patio and chatted.
Now, they (the kids) would have preferred we head over to the MK - but that place is a zoo mid afternoon and it was a Spectromagic night, which means that it would be a zoo all evening. If I had thought we could stay up for Spectro, we would have done that, but I knew we'd be too tired, so we left early.
Other things my kids like to do is swim in the pool...they are more than willing to waste an afternoon in the pool.