Step 1: Convince the revengee to come live with you. This may take some time.Step 2: Acquire an ornery toddler, the barfier the better. This may seem like it would take some time but really all you would need to do is loiter around the toy aisle a Target for long enough and eventually someone would just offer one to you.
Step 3: Acquire an ill-trained, unhousebroken dog. These can be had quite easily. Dogs over 50 lbs. are considered a plus.
Step 4: Give diarrhea to everyone in the house who is approximately 3 ft. tall.
Step 5: Go away for three days, leaving the revengee alone with the toddler and the dog.
Step 6: Success! The revengee will hate you. Nay, haaaaaaate you.
As an added bonus you can come back for a few days and then LEAVE ALL OVER AGAIN. And then plan to go away for every weekend for the whole summer as well.
That'll show 'em.