Here is a 2-hour slide presentation I made for college students and teens:
It's an introduction to realist thinking, a tour of all the good stuff people don't realize until they include a node for their brain's map in their brain's map. All the concepts come from Eliezer's posts on Overcoming Bias.
I presented this to my old youth group while staffing one of their events. In addition to the slide show, I had a browser with various optical illusions open in tabs, and I brought in a bunch of lemons and miracle fruit tablets. They had a good time and stayed engaged.
I hope the slides will be of use to others trying to promote the public understanding of rationality.
Note: When you view the presentation, make sure you can see the speaker notes. They capture the gist of what I was saying while I was showing each slide.
Added 6 years later: I finally made a video of myself presenting this, except this time it was an adult audience. See this discussion post.
Depending on what it meant by the question, either "I'm a pattern of information encoded in my brain" or "I'm a side-effect of processing that my brain does for it's own reasons" are the one-sentence descriptions I'd use.
I identify with the meat that currently contains/creates/executes me, but not perfectly - I don't expect that replacing the meat with a sufficiently-similar replacement would alter the experience of being me.
Identity, of course is a continuum, not a binary measure. A different brain with the same patterns and inputs would be so much like me that I'd call them the same. But really it might be no more similar than future me and past me in the "same" body.
What do you mean "its own reasons"? Do you mean that you exist purely because of your circumstances, or something along the lines of your brain makes decisions, and you're just the qualia it makes when it does it.