this awesome thing is something kids like, i know it i am a kid. My father always puts it up around christmas and then takes it off when it becomes dark so late that you can't see it until 10 pm.
anyhow, this instructable will show you how my father builds it

im sorry for some of the pictures but my camera is failing on me

Step 1: Materials

this is easy
-spotlight
-something for the spotlight to stand on
-tree
-3 pieces of wood, you will be able to determine the size by looking at the picture

Step 2: Setting Up

point your spotlight at the sky and then tilt it a bit so it shines on the tree, note that the spotlight is to be on the side of the tree you are not watching. then put the 3 pieces of wood so that they block the spot from sight (also on the not viewed side of the tree, picture)
then plug it in and enjoy