It would be remiss of us not to provide you with hours of reading pleasure by linking to this explanation of the word MacGuffin.
Black-Robed Figure: Listen you fools! I have to get up to the Trade Federation headquarters!
Obi-Wan: What for?
Qui-Gon: To bring our heads to his evil masters, no doubt.
Black-Robed Figure: Do you chumps think the Lost Orb is just some fancy MacGuffin? Look, do you know what they're planning to do with it?
Black-Robed Figure: They're going to foil the Gungan battle plans!
Qui-Gon: Not listening! Lah lah lah...
Qui-Gon: It's a trick! Don't listen to him!
Black-Robed Figure: They're going to blow up the moon!
Qui-Gon: Now that... is the silliest thing I have ever heard.