Brazilian Jiu-Jitsu (BJJ) is a martial art, combat sport, and a self defense system that focuses on grappling and especially ground fighting. About 80% of all free fights end on the ground. The art was derived from the Japanese martial art of Kodokan judo in the early 20th century.

It teaches that a smaller, weaker person can successfully defend against a bigger, stronger assailant by using leverage and proper technique—most notably by applying joint-locks and chokeholds to defeat the other person. BJJ training can be used for sport grappling tournaments (gi and no-gi) and mixed martial arts (MMA) competition or self defense.

Today, nearly all MMA fighters train in Brazilian Jiu Jitsu due to the success that past practitioners have had in the sport. 

Vale tudo, meaning "everything allowed", or "anything goes" are full-contact unarmed combat events, with a limited number of rules, that became popular in Brazil during the 20th century. While vale tudo uses techniques from many martial art styles (BJJ), making it similar to modern mixed martial arts competitions, it is a distinct style in its own right.

These sets of instructional video's are really the best there are for self defence purposes;

Mario Sperry Vale Tudo Series 1

This is the complete 6 DVD set of Mario Sperry Vale-Tudo series one. Considered to be the most technical fighter to have ever stepped into a ring, Sperry smashes all barriers of secrecy and knowledge of what it takes to win in the street or Octagon. This series is not just another Jiu-Jitsu video series showing moves without a uniform. Instead, it's a complete fighting style, drastically different and 100% more effective in a real fight than anything you have ever seen before! Mario Sperry Vale-Tudo will teach you every aspect of no-holds-barred fighting from standing techniques to brutal ground finishing strikes & submissions. This Vale-Tudo DVD series also contains live action footage of Mario Sperry in action. See the legendary Zen Machine do the very same moves in real fights as he teaches in this incredible video series!
 
http://www.groundfighter.com/Mario-Sperry-Vale-Tudo-Series-1-Instructional-DVDs/


Gracie Jiu-Jitsu Instructional Set Basics, Intermediate & Advanced

The Original DVD Instructionals that forever changed the world of martial arts featuring Rorion and Royce Gracie.