Hi Ben, I learned about them in *a lot* of years of math classes. I spent about three seconds at each of the following sites, so I'm not sure if they are any good ... [or contradict anything I said earlier, 8>] ... but a really really quick search on google turned up: Cantor Diagonal proof: http://www.seanet.com/~ksbrown/kmath371.htm Cantor Diagonal Argument: http://users.javanet.com/~cloclo/cantdiag.html Barber of Seville paradox: http://pirate.shu.edu/projects/reals/infinity/answers/barber.html HTH, RonL.