Dig a 10-foot deep hole with a post hole digger.
Place the flagpole in the hole.
Mix a batch of cement in the 5-gallon bucket.
Pour the cement into the hole. If it doesn't reach the top of the hole, make a second batch.
Drill a 1-inch hole through the center of the bowling ball. Do not use the existing finger holes because they are not centered.
Slip one end of the rope through the newly-drilled hole so it comes out the other side with enough slack to tie a strong knot.
Slide a 2-inch washer over the end of the rope that came through the bowling ball. Tie the rope to secure the washer in place.
Mix a batch of epoxy and pour it into the top end of the bowling ball. When this dries it will keep the rope from moving inside the ball. It will also secure the washer to the ball from the inside.
Spray paint the ball an obnoxious color, something that can be seen easily in the daytime. If you'd like to you could use glow in the dark paint for a different night time experience.
Lean the ladder, fully extended, against the flagpole. Make sure the cement is hardened first and have a friend nearby to help steady the ladder.
Climb the ladder while holding the free end of the rope.
Tie the free end of the rope to the loop at the top of the flagpole that is usually reserved for the flag pulley system.