Popular general-interest math courses

You might check out When Topology meets Chemistry by Erica Flapan or The Knot Book by Colin Adams.

My university offers a 2nd year course on Discrete math which is very popular. It requires no prerequisite knowledge except highschool algebra. This is basically a university level course on problem solving. It includes puzzles, games, number theory, riddles, as well as basic coding thoery, crytopgraphy and graph theory. The course follows the text "The puzzling Adventures of Dr Echo".

http://books.google.ca/books?id=UvYGqvXfgbcC&printsec=frontcover&dq=%5CThe+Puzzling+Adventures+of+Dr.+Ecco&source=bl&ots=8LlBwI0kE9&sig=ZbW7f9d45RamYiL7G62Nb6UNq8U&hl=en&ei=6LFUTZSCEYa0lQe7pcmTBw&sa=X&oi=book_result&ct=result&resnum=2&ved=0CB8Q6AEwAQ#v=onepage&q&f=false

This is a required course for all students wishing to become math teachers as it explains much of the theory behind the games and puzzles used in elementary school. There is no course website but here are some assignments so you can see what I'm talking about.

http://www.math.ualberta.ca/~bpowell/Math%20222/Exam/Exam%20Review.pdf

http://www.math.ualberta.ca/~bpowell/Math%20222/Assignment%203/Ast%203.pdf

This is probably very late, but for what it's worth...

At Brown, Tom Banchoff sometimes teaches a first-year seminar called "Exploring the Fourth Dimension." (In fact, it looks like he's teaching it this coming fall.)

I don't know what he covers, but it's certainly intended for a very broad audience.