Tent 

RV, trailer, camper (only allowed for events hosted by Gryphon's Nest; you must provide your own power and water, and you must haul off your black water)

Plastic tarp(s) - The ground may be wet from a recent rain and you may want to make shade

Bedding - Air mattresses or a cot, sleeping bag, pillows, etc.

Rope and/or duct tape - It just comes in handy

Chairs

Food - Whatever you can cook at a campfire (clubhouse kitchen is typically not available... depends on the event)

Cooking supplies - Pots, pans, oil, spatula, spoons, plates, cups, utensils,etc.

Cooler - For your refrigerated food items (clubhouse refrigerator not available, depending on event)

Drinking water - Water on-site is potable groundwater, but is sulfurous

Firewood - There is almost always fallen wood on the grounds, but it's not guaranteed

Axe/Handsaw - For fallen wood ONLY

Trash bags - You, not the campground, are responsible for your waste.

Fire extinguisher/water bucket - To put out your campfire

Shovel - To cover up your fire when it's extinguished

Lighting - Candles, tiki torches and fuel, flashlights or lanterns and batteries, etc.

Bathing suit, towel, sunscreen, and bug spray - For the pool/hot tub

Shower supplies - Shampoo, soap, etc.  Toilet paper is provided.

First aid kit

And all the necessities for your fun needs - Drums, guitars, belly dance outfits, kites, hula hoops, costumes, balls, Frisbee, etc.