As an addition to my REAL (sorry Canada; Arena) football replacement candidates piece, I would like to add Canadian football. However, it's not really a replacement since it coincides with the NFL season. Their preseason is already underway and they wrap up on November 25th (CFL official site).
Anyway, I caught this Deadspin article about NBC's new 24-hour sports network that is looking for some live programming. I guess they're going to air some Canadian football this season. I've heard some crazy things about the sport: wider field, three downs, punting into the endzone for points (here's Wikipedia's entry), etc. I could see myself watching a few games, just for the sheer spectacle of it! Seriously, it could be fun.
It's too bad that they don't play during the summer because it would be a highly desirable NFL replacement (much better than the nearly non-existent Arena Football League). So, until August 27th, we will be deprived of CFL action on NBC Sports Network and we will have to make-due with mediocre preseason NFL starting this Sunday.
At this point, I refuse to watch baseball.