Not sure is there any place to hang out, the sports animal says Humperdinck but seems like all really old people go there
Sports, in this case, Sooner Football brings people together with no mind to skin color, age, beliefs or pecking-order in society. It has always been that way. So you should be able to enjoy any public Sooner gathering, even if there are 'really old' people there.
But if you choose to filter out old people and just want to be with younger people, I'm sure there are many hot spots that will make you happy. But I doubt they will be Sooners-themed, unless you can find an OU-student party.
Be sure to spend your entire Saturday at the state fair. There is nothing like it. It's what a real state fair looks like.