Some quotes from here (
http://www.sciflicks.com/spaceballs/quotes.html)
Colonel Sandurz: It's Mega-Maid! She's gone from suck to blow!
Minister: Dearly beloved, we are gathered here today to witness Princess Vespa, daughter of King Roland going right past the altar, heading down the ramp and out the door!
Dark Helmet: Before you die there is something you should know about us, Lone Starr.
Lone Starr: What?
Dark Helmet: I am your father's brother's nephew's cousin's former roommate.
Lone Starr: What's that make us?
Dark Helmet: Absolutely nothing! Which is what you are about to become.
[Watching "Spaceballs: The Movie". They reach "now" in the movie.]
Dark Helmet: What the hell am I looking at? When does this happen in the movie?
Colonel Sandurz: You're looking at now, sir. Everything that happens now is happening now.
Dark Helmet: What happened to then?
Colonel Sandurz: We passed then.
Dark Helmet: When?
Colonel Sandurz: Just now. We're at now now.
Dark Helmet: Go back to then.
Colonel Sandurz: When?
Dark Helmet: Now!
Colonel Sandurz: Now?
Dark Helmet: Now!
Colonel Sandurz: I can't.
Dark Helmet: Why?
Colonel Sandurz: We missed it.
Dark Helmet: When?
Colonel Sandurz: Just now.
Dark Helmet: When will then be now?
Colonel Sandurz: Soon.
[nurse exits]
Dark Helmet: I bet she gives great helmet.
Dark Helmet: WHAT? You went over my helmet?
Lone Starr: So, Lord Helmet, at last we meet again for the first time for the last time.