--- a/src/PhysicsObject.cc	Sun Dec 07 00:46:04 2008 +0000
+++ b/src/PhysicsObject.cc	Sun Dec 07 01:18:59 2008 +0000
@@ -348,15 +348,24 @@
 }
     
 void PhysicsObject::enable (void) {
+    // only enable once until disabled
+    if (alive)
+        return;
+    
+    // mark as alive
     alive = true;
+    
+    // add the world objects list
     world.addPhysicsObject(this);
 }
 
 void PhysicsObject::disable (void) {
+    // mark as disabled
     alive = false;
 }
 
 void PhysicsObject::destroy (void) {
+    // mark as disabled and for deletion
     alive = false;
     shouldDelete = true;
 }