Bidders at the MOCA sale also went wild for the L.A.-based multimedia artist Sterling Ruby’s SP82, 2008, a vaporous pink and green spray painting. Estimated to go for $35,000, the work fetched $260,000. “Charity sales offer opportunities that aren’t available in galleries,’’ says Agopian, referring to the waiting lists for in-demand names like Ruby. Ruby’s dealers—Metro Pictures, in New York, and Marc Foxx, in Los Angeles—usually reserve his works for collectors who have supported him for years; for an eager buyer at the back of the queue, the MOCA sale presented the possibility of instant gratification. “People’s love for a cause will get them in the room,” says Schimmel, “but their love for that work of art is what makes them buy.”

David Mugrabi, of the wealthy art-dealing Mugrabi family, which owns hundreds of Warhols, got a call this past May from the Puerto Rican–born painter Enoc Perez alerting him to the fact that one of Perez’s watercolors inspired by modernist architecture would be sold the following day at a charity auction. The artist had donated LAX, 2008, depicting the curving Los Angeles airport terminal, to a benefit organized by the artist Marcel Dzama for 826NYC, a Brooklyn literacy program. David Zwirner, Dzama’s New York dealer, hosted and helped promote the event. “I’m a big lover of Enoc’s work,” says Mugrabi, who was grateful the artist tipped him off to a sale he wouldn’t have otherwise known about. He sent a staffer with instructions to bid up to $15,000.

Mugrabi got the Perez for $8,000, a price he figures is well below retail. “I was ready to pay a lot more,” he says. “At charity auctions sometimes things will go really high, but sometimes things fall between the cracks.”

That gives collectors without Mugrabi-size bank accounts a shot at finding serious work at a reasonable price. Art writer Phyllis Tuchman (who contributes to Art+Auction) assembled a photography collection salted with major names—including Gregory Crewdson, Katy Grannan and Cindy Sherman—largely from charity auctions. She has promised her trove to the Williams College Museum of Art, where it was exhibited last year.

New collectors can find an entry point to the benefit-sale world in the lower-priced events, such as the annual live auction and art raffle run by the Brooklyn-based nonprofit exhibition space Momenta Art, which raised $40,000 this past spring— a third of its annual budget. Many of these novice bidders go on to buy bigger and more important works. The asset manager James-Keith Brown, now a trustee at the New Museum in New York, cut his connoisseur teeth buying art at that institution’s silent auctions in the early 1990s. “As a young collector, it was a great way to see a survey of, and get a good feel for, new and emerging artists,” says Brown.

But these galas are not all Champagne, canapés and buying opportunities. As success breeds success, the artists, dealers, nonprofits and bidders involved have been forced to adapt to the pressures that come with the rising number of events. Even auctioneers are feeling the impact of the current benefit boom. Requests for his services at the rostrum have ballooned over the past five years, says vice chairman Jamie Niven of Sotheby’s, who has agreed to work 31 charity events this year: “I turn down two for every one I do.” The Phillips chairman and auctioneer Simon de Pury is also overbooked. “This could easily be a full-time job,” he says, adding that he donates both his time and travel expenses. Of course, philanthropy is not an auctioneer’s only motivation in contributing hours and expertise: Wielding the gavel at swank events earns him or her invaluable goodwill and contacts.

“I like to give to organizations that have helped me in the past,” says the New York–based painter Will Cotton, who is known for his candy-infused landscapes. Cotton has contributed works to benefits held by the New York nonprofit exhibition spaces Exit Art and Creative Time, as well as those given by the Whitney Museum of American Art. For him and many other artists, the volume of auctions means that some weeks he fields three or four requests. Last year he created three small paintings especially for a few favored organizations. “I really try not to make it a dashed-off thing,” he says.