I'm sure most of my readers have done this, but on the off chance you haven't, I hope you'll try it!
To make wonderful faux stained glass, you will need construction paper, tissue paper, and clear Contact paper. The latter is easily found in any craft store or in the shelf linings section of Wal-Mart. First, choose a shape. I like to do shapes related to our current theme. This week we're doing Apples, so I drew a 7" apple shape on red construction paper. Cut out your shape, and then "stab" the center with the scissors so you can cut out the middle, leaving an unbroken frame about 3/4" thick. With symmetrical shapes, you can fold the paper in half and cut it that way... the same way you'd make a paper heart. Just make two cuts so it opens to a frame.
Now, cut a piece of Contact paper that is slightly larger than your frame. Peel off the backing and place the frame on the sticky side. For the apple project, I also cut out stems and leaves and stuck those on as well. Next, give the child some tissue paper and have them tear or cut it into small pieces. All they have to do is stick the tissue paper onto the sticky Contact paper inside the frame. Have them cover it up so there is no more stickiness showing.
You have a couple of options for finishing. You can stick the whole thing to a window as-is, although it might look odd if the child put tissue paper outside the frame (which they invariably do). You could also trim it, punch a hole, and hang it up. What I do is put a second piece of Contact paper over the tissue paper side. Press firmly to smooth out bubbles, and then cut off the excess sticky paper. Write their name on the frame with a Sharpie and tape it to a window. Beautiful! A real parent-pleaser, too.
Older students could create and cut their own frames, perhaps using craft knives to cut intricate shapes. There are plenty of online sources of free stained glass patterns that could be used - here's one place to start. Just thicken some of the lines with a marker to make cutting easier. This is a good project for all students to explore color concepts, too, since many hues are formed by the overlapping tissue paper.
By the way, a fun variation on this is to have the kids cover a whole window with tissue paper. If they adhere it with liquid starch it will be easy to remove later. Just paint the glass with a thin layer of starch and stick on the paper. A wide brush works best for covering large areas. You can skip the construction paper frames if you want, or add frames after it dries.