The recession may have hit Hollywood, but during the days leading to the Academy Awards, even Hollywood can overcome grim economic numbers to really get the parties started.

“Oscar week is such an L.A. institution, and there’s always such a great buzz in the air, and excitement. It’s a moment when L.A. feels like the middle of everything,” says Nina Storm, the event manager of Global Green’s seventh annual Pre-Oscar Party, which helped kick things off Wednesday.

That fete was hosted by James Cameron and a slew of famous faces, but as Storm and other party planners tell it, despite the huge box office revenues that “Avatar” and many other films racked up in 2009, the still-sour economy has curbed some of the lavish spending that studios and sponsors used to routinely shower on Oscar’s big weekend. Many major studios with nominated films are not hosting parties, and others are struggling a bit to put on a great fete.

“The recession has affected some things — like donated alcohol is much harder to get,” Storm explains. “That used to be one of the easiest things to get, but it has now become a little more challenging.”

And Norby Walters, the venerable host of the 20th annual Night of 100 Stars viewing party, agrees. “There’s been a cutback in the sponsors, and they are the ones that pay for the party. I only have two big sponsors this year, Bacchus Energy Drink and Picture/Portugal, a new film studio outside Lisbon. I used to get many more,” he says.

Still, there’s no other weekend like Oscar weekend in this town.

“Considering the tough times that we’re in, I was concerned, everyone was concerned, about what this year would be like,” admits Edward Menicheschi, Vanity Fair’s vice president and publisher. The magazine has a whole series of “Campaign Hollywood” Oscar week events lined up at the Palihouse sponsored by BMW, L’Oreal and others, leading up to its big annual party on Sunday, and he says all is well in the world of Oscar partying, as long as your celebration can offer up the A-listers. As Menicheschi explains it, “Things are getting a little better. And it was amazing to me that clients, in a year where so much was cut, at Oscar time, if the event is on-brand and high quality, they find a way.”

Oscar’s big weekend is so big, in fact, that a few of the parties have already taken place midweek.

For example, the aforementioned Global Green fete took place at Avalon Hollywood. The event unveiled an eco-friendly Oscar gown by Jillian Granz for Red Carpet Green Dress, which Suzy Amis Cameron will wear to the Oscars, and celebs contributed $75 to $1,000 to the charity Greener Cities for a Cooler Planet.

“Raising money and awareness for something as important as preserving and conserving our environment makes for a great reason to celebrate the Oscars,” says Storm.

On Thursday, the Beverly Hills Hotel was the scene of the third-annual Essence Black Women Luncheon, where the mag honored Gabourey Sidibe, Cicely Tyson, Mary J. Blige, Zoe Saldana and Queen Latifah, along with 350 “influencers.”

According to Karen Williams, Essence’s associate publisher, the magazine had special reason to celebrate. “We created this because we wanted to find a way to celebrate the wonderful and talented black women in front of and behind the cameras that work in Hollywood, that are often overlooked at awards season. Obviously, this year with ‘Precious,’ there’s an exception, but in a typical year, we thought there was a need for this,” Williams says.

On Thursday, Oscar Wilde: Honoring the Irish in Film event feted J.J. Abrams and Seamus McGarvey at the Ebell of Los Angeles. It was the fifth year of the rollicking U.S.-Irish Alliance celebration of all things Irish, with music by Bell X1 and Jupiter Rising, an invitation-only event with a casual vibe. “I wanted to create something that had the feel like you’re hanging out with your friends at your house,” says Trina Vargo, the president of the U.S.-Irish Alliance. “We encourage people to, please, wear jeans. I just want people not to feel like they have to rush home because they hate what they’re wearing. And so we’ve intentionally tried to make it very casual, very house party.”

Thursday also saw the third annual Women in Film Party, held at Peter Guber’s Bel-Air estate. The town’s most powerful women converged to toast the 2010 female Oscar nominees with overflowing Perrier-Jouet champagne and “lovely gardenia corsages, similar to the ones on the bottle, for all the nominees,” according to event planner Elias Soto of ESE Lifestyle.