Our small campus just had our first dance marathon. It didn't start as a greek event. We had two girls who brought the idea to our Americorps Vista. The first thing you really need is a core interest group to help you get support. Try looking at the Children's Miracle Network to find the closest children's hospital. At their website, they should have a contact for these type of events. They can help you from there. Getting a faculty adviser on board is key. Once you establish the contact, you'll be able to start brainstorming for fundraisers and PR ideas. It's a lot of work, but our campus of appx 1000 people was able to raise over $4000. It's not much compared to PSU, but every dollar helps. Good luck!