Curse of Ham is a Biblical curse that Noah placed upon the descendents of Canaan the sons of Ham. God placed the curse on Ham the son of Noah. Caanan was cursed because Ham looked at his father's tallywalker while he was drunk. 
Racist Christians further go on to say that Canaans descendents are the blacks though the Bible doesn't mention who are the descendants of Caanan. Other Christians deny that the Curse of Ham applies to black people.  The
Moron Mormon Book of Abraham refers to Egyptians  being cursed but mainstream Christians and Jews don't accept that book. The Curse of Ham was used by early Americans to justify slavery.
However, the more liberal Christians believed that it was only a sin for Ham and that he may have gone to Heaven (or at least, by now). Also, the Bible did say that if your relatives were to be cursed, it would never go past the 4th generation (and they may lose comfort on Earth, but would get comfort in Heaven (Though many on this website don't believe in Heaven). In other words, most Liberal Christians don't believe in this curse at all.