I think the Neil Sloane Numberphile episodes are amongst my favourites (along with Cliff Stoll of course) and it's amazing that such a hobby project can become so useful. I think the appeal of his videos is that he introduces sequences as a type of game, draws you in and then later on, the interesting questions are introduced.
Another comment in this thread mentioned that Neil Sloane now has his own channel, and is making some videos [0]. Very fun from that 20 minutes I've watched so far.
