Full Screen Mario is a website created by Josh Goldberg that allows you to play the original Super Mario Bros. in HTML 5. The site recommends playing in Chrome, but it worked in Firefox just fine. You can play all the way through the game or pick a specific level. Plus -- PLUS -- there's a random level generator if you really want to get freaky. I didn't feel like breaking out the whips or handcuffs so I just played from the beginning. Then rage quit after I failed to jump on top of the first flagpole. I dunno, there must have be some faulty coding in the program or something. "I did it on the first try." FAULTY CODING, NOW DROP IT.
Thanks to PYY, who agrees they need to make a browser version of the original Legend of Zelda unless they already have in which case where have you been all my life.