For Halloween this year, I was Bill Nye, The Science Guy:
I was not in possession of bow-tie at the time I took this picture, so the look is a bit incomplete. But I think you can get the jist of the outfit. Total cost of costume: $0.00. Thanks to Charity Braz (for the scientists coat) and Jens Jensen (for the bow-tie, not pictured).
On a side note, I think it was apropos that I went as Bill Nye. We both are engineers, we both work(ed) at Boeing, and we both lived in Seattle. Although, I’m not anywhere near as cool as Bill.