The Backyardigens is a totally awesome show. I love it as much as Jasper does, but he especially loves all the singing and dancing. His face lights up when the intro plays, and he becomes entranced when the episode is particularly song-infused. We let him watch it on occasion - like when we need to clip his fingernails and toenails or when he is acting particularly unruly right while I'm trying to make dinner (and Drew isn't home yet). It works like a charm. His response does vary based on the show's content. Sometimes I find him dancing along with the "kids" on the show, and sometimes I find him in exactly the same position in which I left him (on the couch or on the floor). The one thing we have learned is that he does not like the show to end. The show has a particular format, and the end always has the "kids" going into one of the houses for a snack. As they do that and shut the door behind them Jasper bursts into tears. So now we have to stop the show before it gets to that point to keep him from being too upset.
Here is an example of the show's appeal to him.