Mondays can be a drag, but you can brighten yours up with a free cookie, courtesy of Insomnia Cookies.

The bakery chain -- which delivers warm cookies until 3 a.m. for night owls with sweet tooths -- now has 100 locations nationwide, including 10 in Manhattan. To celebrate, customers at Insomnia stores will receive one free "traditional" cookie with any purchase on Oct. 24, the company said.

Insomnia's traditional flavors include chocolate chunk, M&M, sugar, double chocolate chunk, oatmeal raisin, peanut butter chip, snickerdoodle, double chocolate mint and white chocolate macadamia nut. 

Insomnia has locations in Chelsea, the East Village, Greenwich Village, Lower East Side, midtown, Morningside, Murray Hill, the Upper East Side, the Upper West Side and Wall Street.