From Slate:
Watching Ken Jennings play is like witnessing any great athlete in top form: He's the Michael Jordan of trivia, the Seabiscuit of geekdom. Note his systematic habit of moving down the categories vertically, one by one, rather than skipping around the board. His nearly preternatural ability to land on the hidden Daily Doubles. His obscure betting tactics, which, as near as I can divine, are inspired by an obsessive-compulsive need to end each day's winnings with a round figure. His habit of adding some thematic je ne sais quoi to his answers (which, this being Jeopardy!, are of course phrased as questions.) If the topic is a foreign country, he'll answer in that country's accent, and in answer to one clue about hip-hop music, the ultra-white Ken memorably responded, "What is rap, yo?"
What is
Slate thinking?
"Note his systematic habit of moving down the categories vertically, one by one, rather than skipping around the board"
Yes, I've noted that habit in about 95% of the players.
"His nearly preternatural ability to land on the hidden Daily Doubles."
As he's giving the most correct answers, he gets to pick the next question. Naturally, that gives him, by far, the best chance of landing on Daily Doubles - nothing preternatural about that. It's just the odds.
"His habit of adding some thematic je ne sais quoi to his answers "
Well, I don't know what that is.

in the
tape player:
I'm listening to A Stephen Sondheim Evening and two tapes of shows that I don't think are commercially available (correct me if I'm wrong):
Herringbone, the one-man musical by Skip Kennon and Ellen Fitzhugh
Spilt Milk - the only musical comedy cabaret revue The New Yorker singled out for praise in 1993.