If you are wanting traditional piecing style quilts:
Any block you like, you can supersize, then they only need make 4-6 blocks or so, and the bed quilt is done.
I bought the book by Evelyn Sloppy - Sew One and You're Done - Making a Quilt from a Single Block. It is really good. It just takes the block and enlarges it. For example, you can do one star block to make a lap quilt.
Also, make some regular blocks with piecing, then alternate among some big squares or simple 4 patches.
Good luck, it is so wonderful to teach kids! Be sure to show pics of finished projects.