My favorite was to kill a car's ET without hurting the MPH, which can be a good thing in bracket racing. When you line up against a car dialed in the 10.50 range, you won't expect that he'll be doing nearly 140 mph at the finish line, meaning that you're more likely to make a finish line driving error and give up the race. I used the ESC retard by triggering it off the transbrake button and pulling 25 degrees of timing out of the car on the brake. When the brake is released, the car is down 150 to 200 horsepower (N/A car normally running 38 degrees of timing, pulled back to 13 by the ESC input). However, the horsepower starts ramping back in as the ESC decays out, and the car will still run the MPH but is super-slow in the first 400 feet or so of the track.
We did this with a buddy's car and got from 9.80 @ 138 all-out to 10.49 @ 138 with the ESC trick. Big fun!