Hi Keisha,
Great question! And I have to admit I'm jealous. The
24-Hour Summer Kick-Off Celebration looks like it will be fantastic! You are allowed to leave and re-enter the party during the 24-Hours. From the web site, "From 6:00 AM on Friday, May 22, 2015 till 6:00 AM on May 23, 2015, get ready to laugh bigger and scream louder all day and night long. Featuring a selection of popular attractions, shows, Characters and entertainment for the whole family, it’s a perfect opportunity to show your Disney side."
If you want to enter the Magic Kingdom Park after it reopens for the day at 9 AM on Saturday you will need another ticket. I would imagine you will need to be napping after 24-hours of fun!
Thanks for stopping by the Disney Parks Moms Panel. Please let us know if you have any other questions!
Wishing you a magical vacation,
Amy H