DIANE SAWYER (ABC NEWS)(OC): In offices all over the country today, people were forming lottery pools, asking, are you in? Are you in? After the mega millions jackpot surged to half a billion dollars. It happened after no one claimed last night's drawing. But if you're one of those people chipping in with some pals, a dollar and a dream, there's something you should know. Here is ABC's John Berman to tell you.
JOHN BERMAN (ABC NEWS)(VO): Thinking about diving into that office lottery pool? Beware, the waters might be more treacherous than you think.
ERIC SHANE (LOTTERY ATTORNEY AT FERRER SHANE): Once a pool wins, money changes a situation, and money changes people, it changes everything.
JOHN BERMAN (ABC NEWS)(VO): Florida attorney Eric Shane has seen so many pool problems, his firm lists "assisting in lottery disputes" as an area of expertise. Yes, joining forces and buying more tickets can increase your odds of winning. The problem isn't beating the odds but what happens if you do. In New Jersey this month, a judge ruled a construction worker cheated his five co-workers out of their share of $39 million mega million jackpot. To avoid this pool peril, lawyers advise drafting something like a pool pre-nup.
ERIC SHANE (LOTTERY ATTORNEY AT FERRER SHANE): It should be done a certain specific way with identified members of the pool, with identified rules and a game plan of what would happen if you should win.
JOHN BERMAN (ABC NEWS)(VO): Some tips? Make clear what happens if someone skips a week. Make copies of the tickets and make a list with everyone's name and how much they contributed. Sounds like a buzz kill, but pools are not all poison. In Los Angeles, a group of 16 school workers in a pool won, not once, but twice in less than a year.
LOTTERY WINNER (LOS ANGELES): Exciting. I'm still in shock.
JOHN BERMAN (ABC NEWS)(VO): They each pocketed more than $700,000.
LOTTERY WINNER (LOS ANGELES): Lightening struck twice here at Bandini Elementary School.
JOHN BERMAN (ABC NEWS)(VO): Yes, in some pools, the water is just fine. John Berman, ABC News, New York.