My webmaster Michael Bluejay insisted on providing his own answer first:
Actually, drawing lots wasn’t their first idea for deciding who got Jesus’ robe. First they were going to draw a horse, but they didn’t have the right color crayons. So they each decided to draw whatever they wanted, and one drew Carey while another drew Barrymore. But the judging became an apples-to-oranges kind of comparison so they settled on drawing lots. Of course, everyone likes lots because lots means plentiful. You always see signs that say "Lots for Sale", but you never see a sign that says "Only a Little Bit for Sale". When you think about it, that place "Big Lots" is kind of redundant. It’s like saying "Abundant Abundance". But if companies can get away with saying "Pizza Pizza" (or agar agar) then I guess there’s no problem. Anyway, to answer your question, lots were first used for gambling in Cow Bingo. You know, it’s the game where a cow is placed on a lot marked off in a grid and people bet on which grid square the cow will poop in. The most famous use of lots in gambling is their role as the first part of the LOTtery.
(groan) Now that that’s over with, I asked my friend and bible expert, Tom R. the "Watchman on the Wall", about this. He quoted various bible dictionaries. The bottom line is that lots were not used for gambling but to choose a name randomly. This was accomplished by writing one name each on pieces of wood or stone, putting them in a bottle, and shaking just one out.