It's all to raise money for Four Diamonds, which directly helps young patients fighting childhood cancer.
The organization covers the cost of treatment, helps with innovative care, and invests in research.
"I feel really grateful that Penn state has the opportunity to make an impact like this," said Lauren Gempp, of West Chester.
Every hour, everyone inside the arena participates in the official THON 2023 line dance.
Throughout the weekend participants will be entertained by musical acts, and probably a surprise guest or two.
But the real motivation comes from the kids who've had to confront cancer so early in life.
"In 2014 my cousin was diagnosed with leukemia. Luckily, he's alive and in remission, but no family should have to go through that," said Devon Gelmin, of Lafayette Hill.
Action News will be covering the dance marathon all weekend!
Our coverage includes a half-hour special, "Dance for a Cure: Live from THON."
You can watch that Saturday at 7 p.m. on 6abc and everywhere you stream.
50 Years of THON making an impact