STATE COLLEGE — Hundreds of dancers were ready for a long weekend at Penn State.

The annual Dance Marathon began Friday evening. About 700 dancers must two-step, tango and twist for 46 straight hours before the event ends at 4 p.m. Sunday.

No sitting or sleeping for the caffeine-fueled dancers. They were asked to bring at least eight pairs of socks and a half-dozen T-shirts for the weekend.

Dancers are aided by 15,000 student volunteers in an event that raises money for The Four Diamonds Fund, a charity that benefits pediatric cancer research and care.

Organizers call "THON" the largest student-run philanthropy in the world. They say they've raised $52 million since 1973, including $6.6 million last year.