And finally tonight, the big debate is coming up. And as we know, everyone will be on the lookout for those key moments defining the candidate. But as we've seen in previous elections, it's not always... See More
And finally tonight, the big debate is coming up. And as we know, everyone will be on the lookout for those key moments defining the candidate. But as we've seen in previous elections, it's not always the actual debate we remember, it's sometimes the parody, the impressions, the jokes. And abc's jon karl spokes us the perils. I can't, the third one, i can't. Sorry. Oops. Reporter: Some debate moments just don't need late-night comedians to be memorable. For the rest, there's "saturday night live." Let me just sum up. On track. Stay the course. 1,000 points of light. Governor dukakis rebuttal. I can't believe I'm losing to this guy. Reporter: Over the years, the "snl" parodies have been more memorable sometimes than the debates themselves. Can I call you joe? Of course. Okay, because I cpracticed a couple of zingers where I call you joe. Reporter: When you think of palin facing off against biden, you're probably more likely to think of this. john McCain and i, we're a couple of mavericks. And gosh darn it, we're going to take that maverick energy right to washington and we're going to use it to fix this financial crisis. Reporter: The real al gore was so stiff in his first debate -- I will put medicare and social security in a lockbox. Reporter: -- His staff made him watch this. One of the keys to the lockbox would be kept by the president. Reporter: The real john McCAIN WANDERED AROUND THE STAGE When he debated obama, and so did "snl's" campaign. The parodies aren't just funny. They can matter. That's what makes it so powerful. Reporter: After all, how can the real debate compete with something like this? I know the white house. I know the door out to the rose garden doesn't lock unless you pull it. I know the toilet in the lincoln bedroom will run all night unless you jiggle that handle. Reporter: Jonathan karl, abc news, washington. You got to jiggle it. And we thank you for watching
This transcript has been automatically generated and may not be 100% accurate.