Anyone who’s ever stumbled upon a hidden gem in the Thrift Shop has experienced the thrill of finding treasure amid the stacks of books, games, clothing, kitchen utensils and other odds and ends. The annual Chicken Alley Art Show, set for this Sunday afternoon and now in its sixth season, offers customers the opportunity to purchase the finest art and craft items culled from the shelves over the past year. The proceeds from the event have grown from $3,000 to $40,000 in five years, with all earnings benefitting Martha’s Vineyard Community Services.

The event was inspired by Olga Hirshhorn, who discovered a piece of valuable art in the store one day and suggested a best-of-the-thrift-store sale. The event now draws hundreds of people who descend on the thrift store from 3 to 6 p.m. to find rare and offbeat creations. This year’s show includes a vintage painting from the recently demolished Douglas house on West Chop, an original oil painting by Marston Clough and framed prints from photographer Alison Shaw. For antiquarians there are rare books, some signed by the author. Jewelry items will include a pair of donated 18k solid gold cuff links with embedded coral designs.

“As donations come in all year, the 35-plus volunteers, Sandy [Pratt] and myself pick up items and say, ‘Hey, this will be great for the art show,’ ” says Dolly Campbell. “You never know what will turn up.”

One year volunteers found a Tiffany alarm clock at the bottom of a plastic bag amidst a pile of clothes. Sale items are set aside in storage containers until the weekend of the sale, at which point they are priced and displayed. This year over 1,000 pieces of framed art will be on display. When the show begins at 3 p.m., people rush in to see what’s available.

“Its a great big happening, like Filene’s Basement in the first hour,” Ms. Campbell says. “We have an army of volunteers. It’s a lot of fun. It’s amazing that everything is donated, that people don’t realize what great stuff they have.”

According to Ms. Pratt, the Chicken Alley Art Show features an unusual mix of artwork that is rarely grouped together. Visitors might discover fine art, European art, and bizarre pieces that defy categorization.

“We have stuff from everywhere,” she says. “You don’t normally find that kind of eclectic assortment in one show

She says the event brings the whole volunteer staff together as they empty out containers of items that were stowed away months ago, many of which have been forgotten in the hustle and bustle of the shop.

“You revisit all the stuff you put away last January in the middle of winter,” she says.

The eclectic, offbeat nature of the event, in which fine art mingles with offbeat novelty pieces, gives it a casual, festive air.

“I don’t know that anyone else does an event like this,” Ms. Pratt says. “It’s rare to find a show that’s this extensive.”

The Chicken Alley Art Show is Sunday, August 17, from 3 to 6 p.m. at the Thrift Shop on Lagoon avenue in Vineyard Haven.