Has marriage become a joke?
What do you mean by a joke? Yes, it is joked about, but if you mean 'has marriage become a humorous fallacy', no it hasn't. It is still the primary means of ensuring companionship, cohabitation and reproduction.
Is it an outdated concept?
Perhaps. The current definition of marriage as 'man + woman' is being changed. Civil rights for homosexuals are gaining ground all over the world, and soon marriage will include gay marriage as well.
Why get married?
Love, companionship, reproduction. If you really care about another human being on a deep, personal level, marriage is a sign of this. Every living organism's basic instinct is to reproduce, continue the line. Marriage is the civilized, socially acceptable way of doing this.
Do you want to?
Maybe one day.
Should all kids be born out of marriage so not to hurt them?
This is a complex question, and it's answer depends on a range of social and legal issues. While it isn't absolutely necessary, marriage is somewhat binding, meaning that it's more likely to keep the parents together, or at least keep them paying for the kids. I guess if you're willing to have a child with someone you should be willing to marry them.
In regards to the increasing divorce, I haven't done an in-depth study of the socioeconomic factors that cause it, but I think having increasingly nuclear families is preferable to having families where spouses hate each other but stay together.
I do disagree with XxJoJoxX above in that I think same-sex couples make as good, if not better parents than heterosexual couples. For one, they adopt, thus they don't add to the population boom. They give parentless kids a good home and reduce the burden on halfway houses and the state. They also the absolute lowest records of child abuse of any demographic. There is absolutely no research to back up the claim that homosexual couples make bad parents.
Gender: