Would a game of skill that charged a small fee (ten cents or so) per play and paid the top players a cash prize be legal in the US?
I’m thinking maybe something like hangman, or a first person shooter that paid the person with the most kills.
Has anything like this been attempted in the US?
Yeah, it’s called a game tournament.
Yeah, there are pay-to-enter with pay-out LAN tournaments, online tournaments, etc. all the time.
Just look at Starcraft 2, Heroes of Newerth, Counter Strike, or Team Fortress 2.
I think you’ll find a lot of regulation has to do with Games of Chance, versus Games of Skill.
A lot of games in casinos, or lotteries, are games of chance, to give you some idea.
You better consult with a lawyer. There are many many rules and regulations. Any game that charges for a chance to win a prize is deemed a lottery, and under very high regulation in the US.
weird country “USA” 
a too nervous country…
not really
in switzerland you need a license to offer anything with cash payout and high chance is that you will not get any at all actually.
gamble etc is completely ruled and you have to pay taxes on what you win etc
You’re “supposed” to pay taxes on prize winnings in the US as well, but it doesn’t happen a lot of the time since the individual is responsible.
here its simple: you only get 65% of what you win, the other 35% are kept back and payed back when you put it onto your taxes, but you then lose the percentage for the tax (which is naturally quite a bit smaller)
exceptions are stuff comparable to one armed bandit etc where you get cash directly … but the average payout expectation is < 0 so the gov does not need to have the 35% there, you will lose anyway on the longer run (and for placing them you need a special ok, for each of them)
The only site I know is GameDuell.
Don’t know if it is US based.