The annual epic weekend of grooving, line-dancing and two-stepping for charity has arrived at Penn State.

The IFC/Panhellenic Dance Marathon stretches for a grueling 46 hours for more than 700 dancers. They must stay on their feet until 4 p.m. Sunday.

THON, as it's known to students and alumni, is a signature event on the school calendar. It's billed as the largest student-run philanthropy in the world.

About 4,000 volunteers are involved with putting on the show at the Jordan Center, transforming the basketball arena into a sprawling dance floor.

Students have raised more than $88 million over almost three dozen years for the Four Diamonds Fund at Penn State Hershey Children's Hospital to benefit pediatric cancer research and care. The event took in a record $10.68 million last year.