It's the Happiest 24 Hours on Earth. Disneyland and Disney California Adventure opened their doors to hundreds of customers at 6 a.m. today and will remain open for 24 straight hours. The all-nighter event expected to attract tens of thousands of people to the Anaheim parks and the Magic Kingdom park in Orlando, Florida, is a tie-in to Disney's new animated feature "Monsters University." It's the first time all three parks have been opened for 24 straight hours. Some visitors decided to camp out Thursday night in front of the Disneyland gates in anticipation of the big event.