Here's my packing list. Others are invited to add to it...

PACKING LIST FOR FESTIVALS & CAMPOUTS:

Basic clothes:,
Jeans
t-shirts
underwear/socks
sneakers/boots
sweatshirts.

Cold/wet weather clothes:
jackets
sweaters
long underwear (?)
mud boots
ponchos
groundcloths
plastic bags for insts., etc.

Hot weather clothes:
Shorts
swimsuits
sun hats (esp. AAFOUF hat)

Instruments:
Guitar(s)
Phiddle(s)

Music accessories:
Picks
capo(es)
extra strings for all instruments
tuner
songlist(s)
space blanket (for sun)
poly sheet (for rain)
instrument stands

Misc. survival stuff: Lounge chairs
flashlights (that work!)
bod soap, (old) towels
toothbrushes, paste
shaver (if more than 3 days!)
Sunscreen
bug dope
kleenex
toilet paper (they run out!)
handi-wipes
first aid cream
band-aids
tweezers
MONEY
credit cards
checkbooks
note paper
pens/pencils
clothesline/rope
clothespins
bungee cords

Sleep & Shelter:
Sleeping bags
foam pads or air mattresses
pillows
tent
poly sheet for sub-floor for tent
shade awning
hatchet or mallet for tent pegs

Food & Drink & Cooking:

Cooler with:
soda
ice water
cold food & snacks
beer
folding table
sufficient platters, dishes, cups,
condiments

(only if planning to cook):
Cooler w/perishables
non-perishable dry foods
stove & fuel
cooking utensils (especially a teapot)
dishwashing stuff - dishtowels, brillo, soap, etc.
paper towels (lots - damn the environment!)