Photo by Timothy Forbes Photography

FREE WINE: It’s the Grape Festival, and Zaytinya (701 Ninth Street NW) is hosting a complimentary wine tastings with The Country Vintner tonight. 4-6:30 p.m. Free.

DEFENDING UNIONS: Yesterday was Labor Day, a federal holiday that came about due to the advocacy of union leaders. These days, though, unions aren’t particularly popular. Author and activists Bill Fletcher speaks tonight at Busboys and Poets (Fifth and K Street NW) to unpack exactly why and debunk the 21 myths that have made them unpopular over the years. 6 p.m. Free.

PROMOTING PUBLIC EDUCATION: Famed education author and activists Jonathan Kozol has been working to improve inner-city schools for decades, and today he heads to Sidwell Friends (3825 Wisconsin Avenue NW) for a reading and discussion of his latest book, Fire in the Ashes: Twenty-Five Years Among the Poorest Children in America. 7 p.m. Tickets are $12, or you can get in for free if you buy the book at the door.

BEN HARPER UNPLUGGED: Ben Harper’s a talented songwriter and guitarist, and there’s no better way than today’s solo acoustic show at Wolf Trap Filene Center (1645 Trap Road, Vienna, VA) to enjoy his music in its barest form. Rickie Lee Jones opens. 7:30 p.m., tickets range from $35 for lawn to $50 for in-house.