Live' veterans participated in a "Tonight Show Joke Off," a riff on SNL's "Weekend Update" segment during which they battled it out for the best punchlines.

As the show gears up to celebrate its milestone, here are 12 moments over the past five decades when the show didn't just reflect pop culture — it drove it.

NBC's three-hour 2015 special featured A-listers playing classic Saturday Night Live characters and so. many. cameos. Revisit ...