I know how to do that and I'll get right on it!
Todd: Replace the "head" as in the tiny circular top piece that's either a 1/2 circle, 1/4 circle, etc? This piece seems to be working fine it's the piece of pvc that comes out of the ground that seems to be twisting.
OK, I need help. Everytime my sprinkler heads pop up at least two of them are spraying the driveway instead of the lawn. I have 1/2 circle heads on them. I got out my pliers and twisted the pipe so that they now spray the lawn but everytime they come back on, they've re-twisted to face the driveway! How do I keep them in position?