This is true blue football. A BYU homecoming tradition that is very well attended, and it isn't just by the freshmen. The appeal of playing in blue foam attracts many different ages of students.
The blue, foamy students quickly make those without any foam on them blue as well. Literally. The foam will stain both skin and clothes. It washes off quite easily, but to be safe, it is a good idea to wear clothes that can be ruined.
Yes, all those people standing in a line are waiting for their turn on the slip 'n slide. Yes, I had to wait in that line. Twice. Was it worth it? Absolutely.
I went down once on each of the slides, and the left slide is far superior. The hill is slightly steeper, and the foam pit at the bottom is bigger. In fact, the pit is so tall that when students come sliding into it they can't be seen until they stand up, and then try to reorient themselves. The foam covered their eyes (unless they chose to wear the goggles) so they would sort of stumble around while trying to find where their friends went. It was quite entertaining to watch, but not very much fun to have to experience. Not being able to see or hear makes finding your friends rather difficult, but these consequences are a small price to pay for the fun that will be experienced from sliding down through the blue foam.
If you ever have the opportunity to go down a slip 'n slide covered with firefighter foam this is my advice: keep your mouth closed, the foam will make you feel like you're suffocating if you have the misfortune of inhaling it.