An event, meeting, happenstance, occasion or other occurrence that warrants a vague reference or subtle deception when somebody asks about it. Often used during phone conversations when one person is in a place they shouldn't be.
"Where were you last night? I called you like, I don't know, 15 times!"
"Well, I had this whole schmagoola over at Lenny's place, and I couldn't tear myself away from it, babe, y'know?"
"Yeh, ma, it's fine... No, just another one of their schmagoolas, nothing in particular, some wine and cheese, the usual pack of twead-coated sycophants" (He's actually at a strip club doing lines in the bathroom)