Guided tours of Grand Central Station are only offered two days a week. They are sponsored by The Municipal Arts Society and The Grand Central Sponsorship. The MAS sponsored tour takes place every Wednesday a little after noon, when a tour guide is available to lead a group tour. Meet with the tour guide at the information booth on the Main Concourse and consider making a $10 donation per person, which isn't mandatory but is appreciated. Be aware that this is a shorter tour and won't take you to more extensive areas, such as nearby neighborhoods. Call 212-935-3960 to get more information.
The Grand Central Sponsorship tour is a little longer at 90 minutes and is only offered on Fridays. Meet with a tour guide across the street from Grand Central Station at Sculpture Court of the Whitney Museum at Altria. This tour is free and also goes outside the station and into the historic surrounding neighborhoods. Call 212-883-2420 to find out more.
You can also take a self-guided tour through all of the popular attractions within Grand Central Station's Main Concourse. Start at the four-sided clock, otherwise known as the round information booth. Look overhead to the massive astronomy mural on the sky ceiling, painted by French painter Paul Helleu. The stars depicted in the painting are lit using fiber optic technology. From there, admire the gold chandeliers hanging in the Concourse and the stone work around the area in the shape of stones and oak leaves. Don't miss the whispering gallery, where you can stand on each end of the room and hear someone whispering to you from the other side. To end, see the Kissing Room, where notables throughout history would meet and kiss their loved ones here after exiting the trains.