An anecdote or fact someone tells to make him/herself look like he/she actually knows something. Comes from Star Trek TOS, in which Ensign Pavel Chekov says that basically everything is a "Russian inwention" and why, leading to Kirk, in one episode whilst Sulu is launching into a complicated anecdote about Siberia, to announce that "if he wanted a Russian history lesson, he would have brought Mr. Chekov along".
Me: Oh, look. Flowers.
You: Oh yes, those are crocuses, the only flower that can grow in snow. I have a friend who genetically engineered crocuses and planted them on the moon-
Me: Please spare me the Russian history lesson.
You: (have just been owned)