Today we're clearing through world 4. Of the 8 worlds, this one is probably my favorite, despite me grumbling about the lakitu.
Here is a link to the LPer I mentioned, as well as the playlist to his Super Mario Bros. run.
SlimKirby - https://www.youtube.com/user/SlimKirby
[LP] Super Mario All-Stars - https://www.youtube.com/playlist?list=PL8FE0853A399C6899
The playlist actually covers all 4 games, so if you're eager to see the Super Mario Bros. game and then some, definitely give that a look see. Also, as always, if you don't know who this person is, go check them out. They might be another person you'll REALLY enjoy watching produce videos.