Stock under the "Varied" items, and look very similar to the books that stock there as well. The best way to see if you are looking at a book or a movie is to click the item, then read the description.

Once you have purchased a movie, simply put it on your peep, and the whole family will go watch tv

there are three different ones. To get the trophy you have to watch all three. Watching the same one twice doesn't help you.

be different. My family just got the trophy watching Turtle Adventures twice and a different one once. And, the TV doesn't have to even be on. I gave them the first two before I realized the remote was missing and got the "Confused" action line, but still earned the trophy upon giving them the third DVD.