Check out this amazing YouTube video for casuals (the term used for MMA fans that don't have much in depth knowledge of the sport).

Worth a watch if you are totally new to MMA or the UFC. The important thing to always remember is that the UFC isn't a sport, it is a promotion, an entertainment brand. MMA (mixed martial arts) is the sport, there are many promotions that provide MMA entertainment but the UFC is the premium promotion.

Enjoy!