We do things a little differently in Washington. Here, August is the cruelest month and September the coolest -- at least in social terms. Look at all those smiling faces: people just back from vacation, tanned, rested and ready; newcomers still goggling at the museums and memorials; schoolchildren clutching at some of the last free weekends. Even the cooler, clearer weather seems positively festive after August's Sturm und Drang.

So it's no wonder we've taken such a fancy to September. In fact, we've practically invented a new holiday: Second September. The second Saturday, the second Sunday. Lots of Washingtonians still travel on Labor Day, so the second weekend in September is like a big welcome home party, a chance to reacquaint yourself with your neighbors, your culture (and theirs), your arts communities and your favorite performers, and take a last long whiff of fresh grass and grease paint. It has become such a popular idea that it stretches into next week and even a little after that. Even better, it's all free!

All of the big gatherings this weekend are accessible by Metro, although some require a bit of a walk. (Most of those have shuttle buses.) All events are rain or shine. Service animals are always welcome, and the Adams Morgan and Old Town Alexandria neighborhoods are famously pro-dog. But many festivals discourage pets because of the possibility of fights or "accidents," so use your common sense. At the very least, pack the plastic bags.

In the wake of Hurricane Katrina, several festivals have added donation jars or information booths for victims relief, so you may want to bring extra money. The Kennedy Center also will host an American Red Cross bloodmobile Saturday from 10:30 to 6.

Is this your first Second September? Well, come on down. We'll give you a little flavor of the seven big events of the weekend, hit the highlights for you and suggest why certain festivals may suit you or the family better. Using Metro and avoiding parking and traffic, you could conceivably get a taste of all of them -- the very meaning of a SmarTrip card.

This year the second Sunday in September coincides with the anniversary of the 9/11 tragedy, and there are special observances that may place extra pressure on Metro: the free public viewing of the 9/11 Victims Memorial Quilt at George Washington University's Smith Center, which is beside the Foggy Bottom-GWU stop, and Sunday's Freedom Walk from the Pentagon to the Mall, which concludes near the Lincoln Memorial reflecting pool.

So allow extra time, be considerate of out-of-towners who may need a little assistance and appreciate these gatherings as well as enjoy them. That rude winter wind will be blowing soon enough.