How many blonde heiresses does it take to unscrew a lightbulb? None — the heiress's housekeeper does the dirty work.

At a press conference in Berlin on Wednesday, Hollywood's favorite dim bulb, Paris Hilton, shared her personal contributions to protecting the environment. "I changed all the light bulbs to energy-safe light bulbs and I'm buying a hybrid car right now," said the 26-year-old, who claims she turns off the lights, TV and running water (thank God!) when she leaves her mansion. "Little things that people can do every day to make a huge difference."

Kudos, Paris. Now about that gold paint all over your body for this photo shot in Berlin (an ad for wine in a can!) ... I hope it had little or no VOC (volatile organic compound) emissions - or whatever it was I learned from Brad Pitt last week.

Another week, another naked celebrity — but it's all for a good cause.

We Own the Night star Eva Mendes took it all off for PETA's "I'd Rather Go Naked Than Wear Fur" campaign, which counts Christy Turlington, Pamela Anderson and Alicia Silverstone as alums. In an interview with PETA, Eva talked about how she "ignorantly" wore a fur wrap to her very first movie premiere and PETA sent her a "beautiful letter to comment on my less-than-educated choice. I was so impressed that I vowed to them and myself to never wear real fur ... again." She added: "Personally, I think wearing a baby chinchilla says, 'I'm ignorant,' [not] 'I'm badass.'"

Now if only her celebrity twin, Jennifer Lopez, would follow her lead.

Gwen Stefani — who's like celebrity mom of the year, toting that tyke here, there and everywhere — is doing something for some other kids: students who lost their homes in San Diego fires.

The singer is contributing $166,000 from her Oct. 30 show to the San Diego Foundation's fire relief fund. "When I heard about the devastation of the fires, at first I felt I should cancel my show out of respect," she said in a statement. "But then it occurred to me there might be a more useful solution."

Baby Kingston is gonna grow up to admire his mama.

There was a shindig in Oslo, Norway, honoring Nobel Peace Prize winner Al Gore, so naturally some celebs were in attendance and they were sharing their green tips.

Alicia Keys, who performed at a concert, said she's looked at ways to cut her energy use when she tours. "I burn only candles everywhere," the songstress cracked. "Someone follows me with a lighter."

Uma Thurman told reporters that she has her kids to thank for helping her be environmentally aware. "I've very fortunate in that I have 5 and 9 year olds who are getting a much better education [in environmental issues] than any of the rest of us. So I'm constantly instructed on a daily basis what to do."

As for Melissa Etheridge, she told reporters she drives "one of the largest SUVs you can buy — a Ford Excursion — and said, "I run that bad ass on bio-diesel."

Something makes me want to stay the heck outta her way.