At the free Chilmark Potluck Jam this weekend, music fans will have a chance to bid on a one of a kind piece of local music memorabilia, and to support a good cause at the same time.   

Alex Karalekas, longtime organizer of the off-season free music event held at the Chilmark Community Center, announced he would be auctioning one of his iconic, wooden jam posters at the event on Saturday. Proceeds from the auction will go towards medical expenses for the family of his friend John Baker, a former Islander injured in a hit and run accident off-Island.

“He’s a really great guy and I think he’d do the same for any of us,” said Mr. Karalekas of Mr. Baker, who used to reside on the Vineyard. Mr. Baker was hit on a bike ride in Oregon last month and is at risk of paralysis, Mr. Karalekas said. A GoFundMe page entitled “For John” has been created on his behalf by Mr. Baker’s sister.

The poster’s unique design, created by scribing the jam’s lineup with pen into a wooden shingle, has long been a mainstay of the event, though Mr. Karalekas said he hasn’t created one in over a decade. A shingler by trade, he never has had any shortage of materials.

“I sat down and scribed it the old-fashioned way,” he said. “There is about 10 hours of work and a lot of love put into it.”

The auction this weekend will be joined by a packed lineup of local artists, Mr. Karalekas said, including old potluck jam mainstays and new additions. The event takes place on Saturday, Jan. 7 from 6 to 10 p.m.