Nikola Tesla, certainly one of the most influential scientist ever, and yet a huge unknown to most. Tesla invented AC electricity, the radio, these cool plasma balls that you love to touch, the Death Ray electrical weapon (although unfinished), the wireless transfer of energy, the Tesla Coil (remember these cool things from C&C Red Alert?), the induction motor and many more things that we all have around us today.
"Tesla is often described as the most important scientist and inventor of the modern age, a man who "shed light over the face of Earth. Contemporary biographers of Tesla have regarded him as "The Father of Physics", "The man who invented the twentieth century" and "the patron saint of modern electricity."
Now listen to the coolest fact, he was vegetarian! And an animal lover!
"In his later years Tesla became a vegetarian. In an article for Century Illustrated Magazine he wrote: "It is certainly preferable to raise vegetables, and I think, therefore, that vegetarianism is a commendable departure from the established barbarous habit." Tesla argued that it is wrong to eat uneconomic meat when large numbers of people are starving; he also believed that plant food was "superior to it [meat] in regard to both mechanical and mental performance". He also argued that animal slaughter was "wanton and cruel." Cited from Wikipedia.
It's such a shame he's such an unknown. I found it really inspiring to read about him.