Yes, Santa Claus is real. The name comes from Santa (holy) Nicholaus (claus or Nicholas). He was early church bishop of a place called Myra which is modern day southern Turkey. He lived around the 4th century and was a man who had a great love for Christ, both as the Head of the Church, and in his members, that make up the Church. Legend has it that there was a man named Arius who taught that Jesus was not God (this is a historical fact). This made Bishop Nicholas so mad, that when he was at a meeting of bishops from all over the world(this is called an ecumenical council), he went over and clocked Arius cold. He was imprisoned for this by the Emperor, but was released later once the council declared that Arius was teaching heresy (something that is not true about the Faith). It is for this reason that he became the patron saint of unjust imprisonments and keeping Christ in Christmas. He also did many great things like give money to the poor and help girls marry their future spouses. This is where the tradition of gift giving comes from to celebrate him. It was to imitate the saint.
The reason he dresses so "wierd" is because his outfit is supposed to represent the clothes of a bishop. The triangular hat is a "modernized" mitre ( triangular head wear that a bishop wears in formal liturgical ceremonies like Mass). He wears a red and white suit because red is the color used to represent the Love of God or the Holy Spirit, which he was filled with as seen by the fact that he helped so many people. The white represents purity because he helped so many young girls not have to do immoral things to raise money to get married (in those days a dowry-money a father would have to pay the husband for taking his daughteras his wife). So that's where the red and white suit with a white stripe and triangular hat comes from. As for the reason he always says "Ho, ho, ho", your guess is as good as mine!
