i did a thread about the equinox... but there were some lovely ideas there that you could certainly "borrow"... i mean, it's not like they involve dancing naked in the forest....
gather & dry herbs
make bread from scratch
walk in the woods and gather fallen items
fall gardening: if your garden, like mine, still feels very "summery," maybe plant a pot of fall plants... we did one with some millet, and it really helps me to have something that *looks* like fall.
roasted grapes (from sunset magazine): roast bunches of grapes on a baking sheet at 350*, turning occasionally, until juices carmalize, 40 to 45 minutes. serve with baugette toasts and blue cheese
grape dessert (also from sunset): fill a shallow ramekin with a single layer of halved grapes. spread thickly with whole milk greek yogurt. sprinkle generously with dark brown sugar. broil 6 inches from heat until sugar is bubbling, 3 to 4 minutes.
my easy squash pasta: make a pot of your favorite pasta. meanwhile, cook a bag of frozen butternut squash either in the microwave or on the stove (i find it holds up better in the microwave). make a sauce of white wine, garlic, and chili flakes. mix sauce into pasta. top bowls of pasta with the squash, sprinkle with parm, and drizzle with balsamic.