Flash was an almost required plugin at it's height. There was websites that had only enough HTML to display a flash file and the whole website was made in flash. Needless too say, there are still sutch websites (see Homestar Runner). This doesn't even address Flash games which were equally as can't-step-but-five-feet-without-banging-your-shin-on-one as flash only websites. They are still prevolent as well! Just look at Nitrome.
For a download of Macromedia flash, please do click HERE.