There isn't an exact number of how many music genres are out there. It's almost like asking how many colours there are in the world, but here are some well known and popular music genres: Alternative, Blues, Classical, Country, Dance, Electronic, Holiday, Jazz, Pop, R&B, and Rock. I found some basic facts about each well-known type of music genre:
Pop: The lyrics in pop music often deal with love, loss, emotion, or dancing.
Rock: Rock n' Roll music started in the mid 1950's.
Rap: Started in the 1970's in New York City. Snoop Dogg (a famous rapper) was given his name by his mother her thought his eyes looked like Snoopy from Charlie Brown.
Classical: 'Classical' wasn't the term used to describe this music until the early 19th century. Also, classical music month is in September.
Blues: Blues music was invented in New Orleans by slaves to express their sad feelings.
Country: Country music started in the 1920's in Southern United States
Sources: Wiki Answers, eHow.com
