Even the professional puzzle makers, magicians and mathematicians seem to walk around the rooms slack jawed, gazing at walls of display cases of antique puzzles, bingo sets, dexterity tricks, impossible objects.

Forget ships in bottles -- how did the inventor Harry Eng get a tennis ball, two sneakers, a deck of cards, a pack of cigarettes and a dictionary into a narrow necked-jug that seems locked from the inside?

Devotees of mathematics, magic and games come together for three days every two years, sharing their analyses and inventions, paying tribute to the man who inspired them all: the one-time columnist for Scientific American, Martin Gardner.

Some are professionals at play, others have professions that actually are play.