If you’re in the Grand Central Terminal area Tuesday or just sitting around looking for something to do, Metro has a sure-bet for you -- and it’s free.

Through 3:30 p.m., go check out the MTA’s annual auditions for its Music Under New York program.

Seventy acts -- individuals and groups will duke it out in Grand Central Terminal’s Vanderbilt Hall, located north of the clock in the main terminal.

The acts will play in front of a panel of judges who will make the final decision on who gets to play in more than 30 locations within the transit system.

MTA Arts & Design runs the show, so to speak, and says the program is meant to “enhance the station environment and commuting experience for customers.”

And as any rider knows, anything helps!