As others have said, Sbemail marathon starting at episode 1. Though every 30 episodes or so, I'd watch the Halloween and Decemberween cartoons (as well as any other seasonal cartoons they put out).
Also pro-tip: keep the wiki open for the cartoon you're watching. I've been watching this stuff since it began "airing", and never used the wiki. Then about 4/5 years ago I started using it, and realized I had missed like 30% of the content they put out.
Also also, once you hit sbemail 120 or so, give the games a try. Peasant's Quest will always be my favorite.