I always say "I run a small company" and leave it as that. I've never really liked the term entrepreneur as it conjures up a certain image in people's minds and it's not always a good one in the UK.

If people want more specifics I say that I am "a technical director, but in a 2 person company that just means I make the coffee before meetings!" I'm normally much more interested in what they have to say about what they do.

I prefer to tell people I'm the Chief Email Officer. It accurately describes what I do most of the time as CEO.