Is it permissible to play maysir (gambling) and donate its money to orphans and the poor without taking anything from it?

It is not permissible to gamble, as it is one of the major sins. Donating its earnings to orphans and the poor does not make it permissible, as this is among the benefits that are negated by its sinfulness. Donated money is not considered an accepted charity unless it comes from a lawful earning, because Allah only accepts from the righteous and only accepts what is good. Whoever spends from unlawful earnings will not receive a reward; rather, they will bear a burden and be cast into Hellfire for it.