Oh, yeah, that's the Big Mama's and Papa's Pizzeria contest. That's here in LA.
My brothers and 4 of their friends won this contest sometime around Christmas a year and a half ago, not too long after they changed the rules from 5 people to 8 people.
They lied and said they were super lactose-intolerant, so the big pie was served without any cheese. That was the key -- they usually serve it with tons and tons and TONS of extra cheese, just to ensure that it's devilishly hard (and painful to the stomach) to win.
The rules included "no going to the bathroom" -- presumably so that no one could go bulimic-style and simply empty out their stomach for more.
Even so, it was pretty hard for them to finish. This pizza measures 54 x 54 inches. It's about the same size as 20 large pizzas from Domino's, so, each of them still had to eat the equivalent of 2.5 large pizzas each.
If the pizzas had been served with the usual slopload of extra cheese, there's NO WAY they would have been able to hold it all down. Uh-uh.
I think they changed the rules after my brothers' group won, so that now you HAVE to eat the pizza with all the cheese on it. Ugh.
Oh, and, the prize was $1000 for the GROUP, unforch. Not $1000 per person, ahahah.