Using a decoupage technique on an old jar makes a great candle holder.  This is a great project for gift-giving occasions like mother's day, father's day and the winter holidays.  You'll need a clean glass jar (baby food jar, or any size up to a spaghetti sauce jar), tissue paper (whatever colors you like), glue and a paint brush.

Mix about 3 parts glue and 1 part water in a container.  Tear tissue paper into small pieces (about 2" diameter or so is easy to work with).  Let kids use the brush to coat the outside of the jar with the glue mixture, then apply pieces of tissue paper, overlapping the edges, in any pattern they want.  (This project is a good way to re-use tissue paper from gifts because it does not matter at all if the tissue is wrinkled.)  Make sure all the edges are glued down well.  You can brush over them with the glue, and it really doesn't matter how messy this gets.  Bigger globs of glue will just take longer to dry.

Once they've covered the outside of the jar with paper, and your kids are happy with the design, brush another coat of glue over the whole surface.  This will seal all the edges and give it a shiny finish when it dries.  When dry, put a votive candle inside and watch how the light flickers through the jar as if it's stained glass.  (You can also buy flameless candles at your local craft store.)  Tie a pretty ribbon or piece of raffia around the neck of the jar, and you have a nice decoration or gift.

Options: Kids can also add more designs to your piece if they want to.  One way of using this idea is to cover the jar with all orange tissue paper, using the method described above.  Then cut triangles and a smile from black paper and glue them on to create a jack-o-lantern face.  A great window display for Halloween! For a winter holiday decoration, try first gluing red circles (use a hole punch) and maybe some pine needles onto the jar.  Use white tissue paper to cover over it, and you'll end up with a piece that looks frosted.  Another option is to use this for a vase or treat jar instead of a candle holder.