The summer solstice is one of my favorite days of the year. When I was a kid, it meant we could stay outside and play longer than any other day of the year. And today, I guess it pretty much means the same thing.

Solstice -- which I just learned means the "sun stands still" in Latin -- is one of those almost-holidays that is easy to overlook if I'm not paying attention. Or if I can't make it out to Stonehenge in England to revel in it along with all the thousands of pagans and party-goers who celebrate it there each year.

When I am paying attention, I try to do something special (a hike, a bike ride, an extra hour drinking beer on a patio somewhere) to commemorate the longest day of the year. But this year, I'll raise the stakes and try to do something that's eco-friendly as well.

Ancient civilizations based a great deal on the solistice. In the pre-Christian era, solstice was the primary celebration, and that tradition lives on in Europe with dances, bonfires, and other festivities. On this continent, the Mayans built their calendar and several temples around the annual solstices and equinoxes. And at the ruins of ancient Pueblo dwellers, such as Chaco Canyon in New Mexico, Native Americans continue to celebrate the holiday with dances and festivities.

Many people seem to have taken a cue from the ancients, and revamped the holiday to reflect their concern for modern-day green issues. They've planned some cool twists to celebrate the solstice.

Take Lights Out London, an initiative to get Brits to turn off their lights for an hour on the longest day of the year. Their hope is to save an hour of electricity, and demonstrate their commitment to the green movement.

Another variation is a solstice hike in Griffith Park in Los Angeles. Six weeks ago, a fire swept through the hillside, and now hikers are invited to go out in the evening and see the new growth and signs of life that are already taking root, despite the devastation.

If I lived in Arizona, I'd go check out the reading room at the Burton Barr Central Library. It seems that they have a solstice celebration that is designed to mark the event through natural light. Apparently, the eco-friendly building highlights the play of sunlight against the library's walls and columns so that they resemble candles.

These events are both festive and green, and they sound like they'd be fun. If I happened to be in the neighborhood, I would join in or go check them out. Instead, I'll let them inspire me to do something a little more environmentally- conscious than I might have done last year to mark the solstice.

Even if that means nothing more than to take the used beer bottles from whatever restaurant patio I find myself on this evening, and recycle them myself.