I saw slot machines (from a cruise ship) on sale at one of those sleazy travelling sales (they feature cheap electronics of unknown brands, black velevet Elvis paintings, etc.) Anyway, the machines are programmed to work only with tokens-but the guy said a slicht modification would enable them to work with quarters. My question: can I set up a casino in my basement, for my family and friends? Or do I have to obtain a gaming license?
It would depend on your state law.
I doubt that any state allows gambling without a license. So, even if the machine was legal in your state, you would need a license to allow anyone(except yourself) to actually “gamble” in your basement.
Here’s a sales site’s page on the law regarding simple possession. No claims as to accuracy; check your own state’s laws yourself 
As far as I know, you’d be in trouble in 100% of these states were you to actually use the machine to facilitate gambling as opposed to entertainment.
-AmbushBug
[sub]I have a slot machine at my desk, at work. Most of my co-workers do.[/sub]
I think the standard disclaimer is for entertainment purposes only.Like sports lines in the daily papers.
Without a permit to run a game-this includes Nevada or any state that allows gambling-you’d be subject to the same laws that govern your local bookie when he gets busted.
To operate a game,legally,you must have a federal gaming stamp.Obviously,if you apply and they grant you one,your business is in the street,as we used to say.
BTW,you can buy the machines in Nevada at various places,if you really want one.
I live in Ohio and I have a friend who makes a very good living selling slot machines.
They are legal for entertainment purposes only.