Super Why, on PBS Kids is M4's favorite show these days. It wasn't until relatively recently that he had a preference and the older three used that to their advantage - feeding him the names of shows they wanted to watch. For the longest time he'd want to watch whatever M.G. picked - so M2 and M3 would pick one show, M.G. and M4 would pick the 2nd show of the day.
Now he is all about Super Why, especially the episodes with the dog character. After bath time he has been running around with this hooded towel on his head singing the theme song!