Macaulay Culkin -- Rocking with Band in NYC, NOT Rushing to Ailing Father's Side

Macaulay Culkin chose the kazoo and his band mates over his estranged father -- who just suffered a massive stroke -- choosing instead to perform in NYC last night.

Macaulay and The Pizza Underground took the stage 2 days after Kit Culkin had a stroke ... and is currently in really bad shape in an Oregon hospital.

As we first told you, family sources say Kit had tried unsuccessfully to get Macaulay's phone number recently ... all in an attempt to reconnect.

You gotta think Mac's heard about his dad's dire situation by now -- and it's possible he could be headed west soon -- but hey ... someone had to play the kazoo solo last night.