Here is a simple tutorial on how to create a functional clock using a disk brake rotor. The rotor was taken off a 1997 Jeep Grand Cherokee (ZJ). When completed, this project can compliment your man cave very nicely.
-Disk brake rotor
-Silicone glue (or another flexible adhesive)
-Rubbing alcohol or another quick drying cleaning product
-Cutting tool (like a Dremel or Jigsaw)
Set down your disk brake rotor.
Drill a hole in the back of the rotor which will enable you to hang it up.
Cut out the center of the clock (a Dremel with a cutting disk works best for this).
Clean the inside of the center of the rotor. Glue the clock into the center of the disk brake rotor using silicone or some other kind of flexible adhesive. Be sure the clock is centered, and let the glue dry with the clock placed with its face down (as in the picture).
Set the time and hang up the clock!