It depends on the context of the question.

There are times when people, friends, and peers (at a major university) ask me that in a sincere and polite manner. In this case I take the time out to explain basic evolutionary theory to the best of my understanding.

On the other hand when a preacher on the street (or on campus) throws that at me, I usually save some of my sharpest repartee for him. 

Wrong again.

So you object to descending from monkeys but you have no problem with you ancestor being some dirt? (read it somewhere else)

Well, in response to the OP, when people say such things in that manner, it usually means that they are unfamiliar with evolution in its entirety, and are employing intuitive and naive notions in order to attempt to discuss complex scientific theories. Since our intuition is often at odds with said complex scientific theories, they will run into some problems doing this. Several days ago I decided to read the mission statement of the Flat Earth Society. It was only a few paragraphs, not enough time for me to vomit, and the spelling and grammar were, um...different. Anyway, they railed on for a bit about the evil scientific conspiracy and the supposed dogmatic, quasi-religious nature of science, and then presented their argument for the Flat Earth (if the Earth is round then how come Australians stand upright? They should be upside down).

Obviously this is complete nonsense. There are no "directions" in space. The notions of "up" and "down" are meaningless. They are applied in daily life only relative to the ground on which one is standing. It is a non sequitur to say that people on the North pole should stand upright and those on the south one upside, and everyone else should stand at some slanted angle. Yet intuition tells us so. I wouldn't listen to intuition however, it's useless. Relative to the ground on which an Australian is standing, he is upright. Relative to the ground on which an American is standing, he is also upright. So is everyone else, because that is all motion and position are, they are relative concepts that are only judged in a frame of reference relative to other bodies. The argument the FES put forth above is identical to arguing that if the Earth was moving relative to the Sun at thousands of miles per second, why we do not feel this. The answer is obvious, because if we are standing on the Earth, we are travelling at precisely the same speed, and hence relative to the Earth, are not moving at all.

I picked the most ludicrous example I could find to illustrate a point. When people use intuition to try and understand scientific ideas, they will fail, and this will usually result in using childish language to attempt to mock something regarding which they have precisely zero understanding. In the irritating moving Expelled, Michael Ruse and Richard Dawins explained, in simple language that even someone with cognizance deficiences on the order of magnitude that Ben Stein possesses could understand, which is impressive. They were explaining how elaborate molecular synthesis could form on the backs of rocks, and how piezoelectricity could allow for the assembly of small scale elabore metabolism. They also explained Autocatalysis and clay theory, and the possibility of the synthesis of organic molecules in mud, or water, because of the dipole effect and the high concentrations of organic molecules. Of course, Ben Stein, who knew precisely nothing about primordial biochemistry, electrical organometallic chemistry, or molecular biology , laughed and returned to the point throughout the movie. "MUD"!! (Laughing) "ROCKS"! It was all very Hovindesque in delivery. Of course, this ridicule was all the man could muster, because he was relying on intuition and childish language to try and understand (actually, that's not true. He obviously wasn't trying to understand at all. He was trying to ridicule) something that clearly shot straight over his head. How can one present a serious critique of that which their sum knowledge total is negative (in addition to no knowledge, being in possession of disinformation)? It is incredibly easy to try and fuck up when trying to understand complicated scientific concepts. ("If Relativity is true, how come I can't go and visit my dead relatives?" ).

With respect to evolution, the problem is in some cases greatly exacerbated. There is a lot of potential for complete misunderstanding here. An equally stupid argument could be concocted by reversing the currently employed "Second Law of Thermodynamics" argument to become "If SLOT is true, how come we have all these ordered systems like biology"? One way I find that misunderstanding often springs forth is when people try to use metaphorical ideas and concepts to try and explain ideas. If the laws of thermodynamic are to be understoon in terms of "progressing towards disorder" and evolution, which despite having no implicit direction has, as a general rule of thumb, constructed more complex entities as a function of time, is creating "order", then someone naive can imagine that there is a problem. Such explanations rely on childish and metaphorical understanding of thermodynamics concepts that cannot be understood in any way whatsoever without complete familiarity with the equations. My point is, when people either try to rely on intuition, or a very meager amount of knowledge, the idea that they can "critique" a concept based on this foundation is ludicrous. THe brutal and undeniable fact is that the number of creationists who can give me a single sentence, working, accepted scientific definition of biological evolution, without consulting wikipedia, is utterly negligible.

You think we came from monkeys?  Generally this opinion is held by people that don't really understand evolution.  What do you understand about evolution?

  I just say, I AM of the most fancy monkeys , then I do a monkey dance with special evolved sound effects, my voice ....        <--- see monkey me having fun ....

Is this a question addressed to me or is that the question you ask to those who misunderstand evolution? As for me, I have a Bachelors degree of Science in Zoology, so I would say my personal grasp of the idea is fairly concrete.

"I would rather be a transformed ape than a degenerate son of Adam." Paul Broca

My mother says stuff like that... "You think you came from a monkey!?"

My response is "That's ridiculous, Who said that?"

I remember seeing Richard Dawkins respond in much the same way when someone talks about humans coming about by 'chance'... he even gets mad while he says how ridiculous it is

My best comeback ( inspired by a visit to the primate exhibit ) to that ridiculous question is to:

1.) unbuckle my belt and lower my trousers and underwear

2.) defecate into my right hand

3.) scream wildly while flinging my poop at the person who broached the subject

It's difficult for their superficial argument to stand against a well-reasoned response coupled with a witty presentation as I have outlined here.

Or was it South Park?

LMAO, this is totally the winning comeback for me.

I'm not neurologically 'designed' to come up with witty responses like this to dumbass questions, most likely my reply would be the straightforward and boring fact that 'monkeys' weren't around then. Alas, I am but a simple geek appreciating the cleverness of your humour.

mine is, actually we came from apes. and apes and monkeys both came from something else. then that something and another something which bush babies and the like are related to, came from yet another something. so on and so forth until it gets back to simple dna structures and amino acids. you believe we came from a vain superbeing with a penchant for atrocities?.

please excuse any spelling or grammatical errors, I'm dyslexic

Given the ignorant, mouth breathing twits who typically rail against evolution, I'd simply ask, "would you rather take those assholes as your heritage, or realize that for good or bad, we all come from the same place, we all share a common ancestor, and each and every one of us are linked in some familiar way."

Personally, I'd rather be have an actual monkey for an uncle than a hateful bigot, but we don't get to pick our relatives. That bigot IS related to me, and to all of us, and as far as I'm concerned as long as one member of that family wallows in ignorance or squallor, it is my obligation to do something about that.

Answer to the ubiquitous stupid question, "If we evolved from apes, why are their still apes?"

They diversified and filled new niches. Until recently, they were very successful in these niches. So were we, in our niche, and that's why there might not any apes left outside of zoos in the next century or two.

Also, they're confusing extinction (which is not due to natural selection, just bad luck) with phyletic extinction, which is an evolutionary process that is the result of selection, drift, flow, and other factors.