(sorry about the sideways photo. Wish I could fix it)
This first one is called Scripture Ornaments, and you can download and make your own here. It is a good one for younger children since the ornaments are shaped differently, and you put them on the tree based on finding their matching shape, rather than by finding an answer to a question. There are questions with each one, and you do look up a scripture to find the answer, (ie, Why didn't Mary and Joseph stay in the inn, Luke 2:7) but to hang the decoration, you don't have to get an answer right.
The other is for middle-aged children. Like the first one, it involves looking up a scripture about the birth of Christ and finding the matching picture, but these ones are much more specific, and some pictures are very similar. The kids need to be able to read the summary beneath each picture to find out the right picture. Still really great though and we certainly wouldn't stop doing it because it is more challenging.