Lughnassadh 
There are a total of three harvest celebrations in the Wheel of the Year. Lughnassadh, Mabon, & Samhain. Lughnassadh begins around August 1, or astrologically when the Sun enters Leo at 15 degrees. This is one of the four Great Sabbats, a cross-quarter day, able to be used as an inverse weather predictor.
Lughnassadh is a celebration of the first harvests of the year, thanks to the God for His sacrifice to give them to us, and the Goddess for making it possible. For the Earth IS the Goddess, and crops are the God.
Lughnassadh is Celtic for "Commemoration of Lugh". A Celtic Sun God, Lugh was a smith, craftsman, writer, poet, historian, story-teller, musician, magician, warrior & hero. A 'Jack-of-all-trades'. Celebrations of His gifts are played out as games of strength and endurance, and plenty of show of artistic and entertaining abilities, accompanied by enjoyment of the first fruits, veggies and grains of the year.
These games began as requested from Lugh's foster mother, Tailtiu to celebrate Lugh as the provider to human kind, as well as a remembrance of the pain She went through to prepare Her womb (the Earth) to give birth to Him (as the crops) to grow and be harvested or sacrificed to His people.
SInce grains are the first crops to be ready for harvesting, they are very prevelant in festivities and rituals. Many different recipes and crafts can be made with grain crops. A Harvest doll or Corn dolly is a doll of the embodied spirit of the crop made from the last sheaf of the harvest. Keep the doll to ensure a good crop for the following year.
Berries are another crop in full swing at this time, as well as many herbs and vegetables. Canning and preserving for the cold months begins now.
Some other names for this holiday are Lugnasad, Lughnasadh, Lunasa, Lammas(Anglo-Saxon, "loaf-mass"), Festival of Lugh, Harvest Festival, August Eve, Cornucopia (Strega), Thingtide (Teutonic), etc.

HERBS/FLOWERS/INCENSE:
Grains, Wood Aloes, Cyclamen, Fenugreek, Frankincense, Heather, Hollyhock, Myrtle, Oak, Rose, Rosemary, Sandalwood, Sunflower...
seasonal herbs,flowers,fruits,veggies in your local area.

COLORS:
golden yellow, orange, gold, light brown, green

DECORATIONS:
corn dolls, kirn (corncob) dolls, grains, grain stalks, breads, berries, seasonal nuts, fruits & veggies, harvesting & threshing tools, sun wheels, cornicopias

FOODS:
corn bread(AKA Johnny Cake), grains, breads, cakes, berries, jams, jellies, preserves, pies, nuts, seasonal fruits and vegetables, beer, ale, cider, wine.
GODS & GODDESSES:
Lugh(Celtic), Llew/Lleu(Welsh), Lug, John Barleycorn(Scottish), The Green Man(Celtic), Dionysus(Greek), Mercury(Roman),
Tailtiu(Celtic), Cerridwen(Celtic), Gaia/Gaea(Greek), Demeter(Greek), Ceres(Roman), Tera(Roman), Corn Mother(NativeAmerican)
~agricultural & grain deities~

RITUALS/ACTIVITIES:
prayers for abundance, harvesting crops (grains, fruits, veggies, herbs) for the coming year, canning, baking breads & cakes (make some in the shape of a man or sun to represent the God), making pies, wheat weaving, making grain dolls, craft festivals, harvest festivals, endurance games, handfastings (trial marriages), preparing for Autumn.

ANIMALS/CREATURES:
crows, ravens, eagles, griffins, phoenix, roosters, centaurs

GEMSTONES:
aventurine, citrine, peridot, sardonyx, yellow diamonds
TAROT CARDS:
Justice, Wheel of Fortune
written by GypsyJaguar 2004
also see:
http://www.mythinglinks.org/Lammas.html
http://www.echoedvoices.org/Aug2001/AugLugh.html
http://www.geocities.com/Athens/Agora/3557/Lugh.html