Question: Is there any way to convince a Christian that playing poker is not a sin?
Answer: NO
The reason most Christians that I have encountered believe that gambling in general is a sin is because the Roman soldiers at the foot of the cross cast lots (shot dice maybe) for the cloak and the coat of the Christ as he was being crucified. That is if they even know why their Church has condemned gambling. They seem to forget that the casting of lots was directed by God in order to divine His will on several occasions. (prov 16:32, lev. 16:8-10, joshua 14-21, Num 26:55 33:54 34:13 36:2, I cor24:5 31,25:8-9 26:13-14, and Jon 1:7) and in the New Testiment The casting of lots was used by the Apostles to selest Matthias to fill the spot vacated by Judas in the apostleship. (Acts 1:26) They also think that we are too stupid to controll our bankroll. (That we will go broke and our families will go hungry.) Oh and some of them think that any extra money you have to play poker (gamble) should be given to the Church. This statement is not indicitive of all Christians, just the type you are referring to. Also this statement is only a conjecture from my personal expierience.