A large quantity of something, with diverse variation, served or otherwise open to people. Typically refers to a platter of food at a social gathering. The word is derived from Nordic languages, it's exact source unknown, and is used by Americans of Northern European descent, such as those in the American Midwest.
-"Did you see this, Phil? The Lutheran picnic even has lutefisk!"
-"It's a whole schmorgisborg, Marylis! Let's go home and make whoopie, eh?"