Newark NJ USA Airport Marriott (the one on the grounds of the airport with its own shuttle), update from July 2022: actually October 2022, now that I check my records

Lounge OPEN on weekends

Posted hours, daily:

Breakfast: 6am-9am (ending 10am on Saturday and Sunday)
Hor [sic] D'oeuvres: 5pm-7:30pm
Dessert: 7:30pm-8:30pm
Doors Closed: 11pm

I did not make it for breakfast, so not sure what was served. I did stop later in the day and grabbed a few bottles of water from the fridge. Door was key accessible during the day.

Note that this is NOT the space on a high floor that was created to be the elite lounge. This is a (nice enough) room on the right side of the bar in the lobby, toward the front entrance of the hotel.