Here's an entertaining and informative (if simplified) little cartoon that explains things, sort of - the important thing is that anyone can watch it, and both understand it, and be amused by it:
"This Video Explains Why We Cannot Go Faster than the Speed of Light" on bbc.com
As a bonus, you'll learn what the word "tachyon" means, and you, too, can scratch your head and ask yourself, "Why do they have 'tachyon particles' and 'tachyon beams' in Star Trek?"