I'm sure this is going to seem like a very silly post to some people; however, I ALWAYS dread it when I'm asked this and struggle with providing an answer that is A) accurate and

understandable to your average non-IT person.
I understand that most of the time, this question really is just a formality of small-talk and the person asking probably doesn't even care about your response... And really, I think I'm often better off just making something up: "I'm an uhh... I'm unemployed." At least this response will almost guarantee no follow-up questions!

I guess I am stuck somewhere between rambling on and on to try and actually clarify what it is I do and selling myself short. My official job title will confuse someone, and nearly any response with the word computer or technology in it will lead to a follow-up of... "So you're help desk...?"
Yeah, I suppose it is partially an ego trip. I've given in and said, "Yeah something like that." just to move topics... But at the same time, I'm not help desk. I'm something entirely not help desk. I enjoy my job and enjoy talking about it, but it becomes very difficult to non-IT folks.
My wife explained it to me once -- yes most people comprehend that computer systems comprise the infrastructure of most businesses; however, they're not aware of the complexities within IT and that there are actual
people running these systems.
Beyond that, explaining the OS/UNIX portion of it... Forget about it.

Ending my rant now... Does anyone else ever encounter this dilemma? What's the best way around it?