Use as a Running Gag in ANY Show
Display a beautiful Red Aluminium vase, which can have flowers in it beforehand. You remove the flowers and pour all the water out of it.
You then present another trick. When you come back to the vase, somehow it is again filled mysteriously with water, so you again empty it into a large bucket.
This is continually repeated throughout your show. At the end, you can attempt to pour all the water back into the vase, but it overflows because it will not fit back in!