Raw Materials Art Supplies hosts a weekly life drawing event at Grand Central Market every Friday night from 6pm to 8:30pm. These are uninstructed drawing workshops with live models holding poses up to 20 minutes, with different costumes/theme each week.
There is a $10 suggested donation for the models, and you can pre-register online to reserve an easel and qualify for a free goodie bag (first 20 registrants).
Vendors at Grand Central Market are open late, so you can eat, drink, and draw!