After George tells Mary and Meemaw that he used to listen to Black Sabbath and Satan didn't get his soul, Meemaw asks him, "What happened? Did you trade it for some doughnuts?", which is exactly what Homer Simpson did in a Halloween special.
When Sheldon meets Ira, he shakes Ira's hand, despite Sheldon never shaking peoples hands.
Richard Kind plays a Jewish furniture show owner in the late 1980s. Three years later, in The Goldbergs (2013), also set in the 1980s, Richard Kind's Jewish formica store owner character buys a furniture store.