Was there an episode on this past Sunday (April 28th)?

How many episodes have aired so far?

I don't think there was an episode. I scheduled on my DVR to tape all of the shows, and one didn't tape on Sunday.

There was a new episode. Some NBC stations may've pre-empted it.

Five episodes (seven hours) have aired so far. I usually watch it on WGRZ Buffalo, but for the last 2 weeks they have not shown it because they felt a Buffalo Sabres special each week is better than poker. I then had to watch the poker on Seattle's KingTv (#151 on Rogers Digital) at 6pm eastern time, each Sunday.

You can also watch any episode on the NBC.com website, even from Canada (it works),since no Canadian station owns the rights to it. The website even has a page that will tell you who won the whole thing and the actual length of many of the match-ups.

There are just two more weekends left. May 13th is from Noon-2pm and May 20th is from Noon-3pm.