SilverWook said:

Duke Dooku's severed head won't shut up and die, singing to itself in the background. When the ship changes attitude, his head rolls into the elevator shaft and falls past our heroes, still singing.

I love that idea.

Here are a couple of more that might be funny:

Palpatine: I want you to be the eyes, ears, hands, feet, legs, toes, etc., and voice of the Republic.
Frustrate Palpatine by an endless amount of dialogue by Anakin when Palpatine explains about Darth Plagueis: The movie life as a house has: I don't know what that means. and I still don't know what it means. Palpatine could at one point just give up and walk away. and I'm not even listening.
Yoda: Good relations with the Wookies, I have. (A quick cut to the Star Wars Christmas Special of the Wookie wife and kid)
Kenobi: Did I miss something? (every time he walks into frame)
Vader's speech sounds like a speek & spell with Palpatine or a droid saying that this will be fixed later
Padme: Hold me, like you did by the lake on Naboo; so long ago when there was nothing but our love. No politics, no plotting, no war. (leave it. this is comedy-gold!)
After delivering Luke and Leia, Padme goes on and on about that there is still good in Annie (everyone gets bored and they turn off the lights with her still going on)

Maybe some of this is helpful. :)