In a Review Journal article entitled "These tips may ease tax time" http://www.lvrj.com/business/15155016.html the writer tells the tale of Linda Myers of Minnesota who went to court to defend her slot playing as a legitimate business.
She began playing slots in 1992 after her husband died, spending 35 hours a week in a casino.
That scenario sounds pretty typical, and I'll bet the casino was Mystic Lake, an Indian casino I've spent a few hours in myself outside the Twin Cities.
Here's were the story gets unusual -- Linda claims to have developed winning strategies for the $1 slots. There is only one definitive winning strategy I know of -- Luck!
If you are lucky you could earn a living playing slots, but I doubt anyone would be lucky enough year after year.
Still according to the article she won her argument, and somehow reflected her slot "business" on her taxes.
As for me, this will be the first year I incorporate my slot losses in my tax return. Time will tell how that works out.