Infinity

This won't be everyone's cup-a-tea, but for lay folks with an interest in math, a decent introduction to some of Cantor's notions of 'levels' of infinity here (quite bizarre if you've never encountered them), including his "diagonal" argument/proof:



Part 2 is here.

There are actually a lot of internet videos dealing with infinity --- I'd be interested to hear other people recommend Web-based videos (YouTube or otherwise) that do a particularly good job of explaining these concepts for the lay public.
Further I'd be interested in Web video suggestions for presenting Godel's incompleteness theorem to lay folks, as well (...a more difficult task!).