Dana Carvey’s George Bush. I’d do it now, but it wouldn’t be prudent.
Being a Texan, I can do a pretty mean Boomhauer.
I can also do a good Karen Walker. In the sci-fi vein, I can do Chiana’s (Farscape) mannerisms fairly well; I can also imitate Kaylee from Firefly. Unfortunately, I can also do a good Comic Book Guy from the Simpsons.
My husband is very good at impressions: Beavis, Butthead, Barney (from the Simpsons), Austin Powers, Tim Curry, among others that have momentarily left my mind. Over the phone, his normal speaking voice sounds like Christian Slater.
Yeah, Karen Walker, Homer, Mr. Burns, singing like Roger Waters, some other ones I don’t remember.
“Celebrity Jeopardy” Sean Connery
The peasant from Warcraft II
The Peter Griffin laugh
Quagmire’s “heh heh, awwwww right”
I used to be able to do a pretty good Hannibal Lecter, but it’s not as good as it used to be. It’s gone the way of my various fake accents.
Bert & Ernie, a few other Frank Oz voices (no other Jim Henson voices, though), Patrick Stewart, the obligatory Sean Connery (though I think I do him better than most), and Billy Connolly. And most of the Goons.
Marcel Marceau
Cecil the Sea Sick Sea Serpent
Heh. Me too. I was in service in the mid-nineties, when it came out, and the peasant responses became stock replies at work.
“All right.” “Yes, sir.” “More work?” “I’m not listening!”
On reflection, it’s amazing that I never caught any flak for that.
I was going to say that.
I can also do a decent Harpo Marx. Without the horn, that is.
Oh, and i forgot, i can also do a semi-decent Zoidberg, why not?
did you hear me mimicing? i was all like woobwoobwoobwoob!
Now Zoidberg’s the popular one!
Dirty Harry’s voice is another one i can do a reasonably decent mimic of, as well as Brent Spiner’s Data doing his impersonation of Capt. Picard…
Can i get a Frell Yeah?!
coincidentally, i can do a fairly decent Ka D’Argo mimic (i guess that also means i can also do a fairly decent “Movie theatre trailer guy” voice as it’s what Anth. based his D’Argo voice on
…i can also mimic the “In A World” movie trailer voice guy…
My Richie Benaud is greatly in demand when cricketers get pissed and will laugh at anything. Like many other of my voices, I got this not from the man himself but from someone who impersonated him. It is generally considered that my Michael Parkinson is rubbish. I still use the line that Rory Bremner, or perhaps Mike Yarwood before him used: “Evening, welcome. On my show tonight a man who is quite simply, and I quote, unique. But more of me later.” Still fails to raise a laugh every time. For some reason that is difficult to fathom, I do it every morning as I get out of my car and walk the stairs up to my office.
I used to be able to do a really good impression of Pinky and the Brain, but I can’t do it any more. 
I can sing just like Ethel Merman.
I’m not very good at impersonating Clint Eastwood, but I can do a frightening convincing impression of Ronald Reagan impersonating Clint Eastwood.
Bullwinkle (my best)
Yoda (not that hard to do, it is)
Animal (“Ah, what do? Eat drums!”)
Kemit the Frong (as long as I limit it to “Hi-ho, this is Kermit the Frog”)
Miss Piggy performing a karate chop
Gurgi from The Black Cauldron
Shir Sean, of course
Mugsy and Rocco, the two thugs in Bugs Bunny’s The Unmentionables
Daffy Duck doing his “Robbing Hood” schtick (“Ho! Ha-ha! Guard! Turn! Parry! Dodge! Spin! Ha! Thrust!” (WHAP))
Mickey Mouse
Goofy
I can do a great Riff-Raff (RHPS) and the little dude from Lord of the Ringses.
I do a perfect Thomas Jefferson.
I didn’t do it on purpose, but a couple of weeks ago, I was speaking with a customer on the phone, and he told me I sounded a lot like James Dobson.
Yes, the James Dobson from Focus on the Family. I was so, errrr, flattered, that I needed to take a break and evaluate whether I wanted to ever speak out loud again.
When I want to mimic a character, I often choose Chris Griffin. But I can also manage Brando, Schwarzenegger, and a few others.
No you weren’t.
I can do most of them. My “Hank Hill” is probably the best. I’d give you a sample, but I didn’t get written permission from the producers for “accounts and descriptions” of the original broadcast. So, uh…see ya.