You need an old, non-aluminum cookie sheet, colorful contact paper or self-stick shelf lining, heavy-duty magnets and (if you want to have a pencil cup like in the picture) a clean and empty tin or frozen juice can.
Unroll the contact paper and lay it out flat on a table. Set the cookie sheet upright on the contact paper and use a pencil to trace around the base of the pan. Using scissors, cut the contact paper along the pencil line. Turn the cookie sheet upside down and align the edges of the contact paper to the base of the pan.
Starting at one corner, carefully peel away the contact paper's backing, adhering the contact paper to the base of the pan as you go. (This is the most difficult part, because you don't want to end up with air bubbles between the contact paper and the cookie sheet!) If you end up with an air bubble, carefully push it toward the nearest edge of the contact paper until the air is evacuated.
Add colorful magnets and some note paper to your magnetic message board and hang it by a nail from the hole in the cookie sheet. (If your cookie sheet doesn't come with a hole in one rim, you may have to punch one yourself or fashion another means for hanging it.)
If you want to add a pencil cup, set the can on another flat sheet of contact paper. Mark the height of the can on the contact paper. Starting from one edge of the contact paper, roll the can one complete revolution over the contact paper and mark the place. Add another inch to the length of contact paper you measured to ensure the piece will fit your can well after you cut it out. With a ruler and pencil, trace a rectangle from the points you marked on the contact paper. Cut the contact paper along the pencil lines. Align the edges of the contact paper to the can and carefully apply as you did to the cookie sheet. Glue a couple of heavy-duty magnets to one side of the can. When the glue has set, attach the pencil cup to your bulletin board and drop in a few pens and pencils.
Voila! Your new message board is ready for use.