As we all know, tomorrow is Earth Day, a 30-something-year-old event that has even greater significance now as the threat of global warming looms. If you want to curb your carbon emissions and do your bit for the environment, here’s a chance to not only save money on gas but pocket a crisp $100: 511 Rideshare, the free Bay Area Web and phone service that helps match commuters to carpools, is offering up to $100 in gas gift cards if you switch to carpooling (no fair if you’re already doing it … though, good on you!)

The program starts today, so you can cruise over to www.511.org or call (510) 273-3600 to get started. I’m interested to know: How many readers have changed your behavior - cloth shopping bag, compact fluourescent light bulb, more frequent BART trips - to be environmentally friendly? What tips do you have on going green? (Photo: tyger_lyllie)

The light bulb should go on in a big way for consumers tomorrow - the compact fluorescent, that is - as a new lamp using half the electricity of conventional lighting goes on sale. The low-energy but high-tech Berkeley Lamp II was designed by the California Lighting Technology Center at UC Davis in tandem with private company Full Spectrum Solutions. The lamp aims to solve problems many have found with the energy-saving fluorescent bulbs (pictured above; photo by slightfoot on flickr): dim, less-than-pearly-white light. Fiat lux!