Congratulations to @LouisvilleSoup who broke 24 minutes as well.
I arrived close to 7 am at the Falls of the Ohio State Park, and ran a mile warm-up. The air had felt chilly all morning until that point at around 60 degrees.
After finishing my warm-up, the air didn't feel so crisp and cool anymore, but it was still comfortable--probably about as warm I could stand for a medium distance race. I lined up in the second row of people, maybe about 10-12 people wide, and took off like a bat out of hell for the first several hundred feet. The first km split was at a 6'41" pace. As far as I remember, from that point on, no one passed me. I spent the rest of the race trying to catch up with people out in front of me.
By the fourth kilometer, I started to feel some fatigue and lost a little motivation to finish the job. I tried focusing in on a guy who seemed to be pacing the perfect 5k race, and pushed myself to get past him.
With the finish clock in plain sight, I saw 20:45 heading into the corral. I sprinted in for the finish at 20:59 (6'46" pace).
2nd3rd (received 2nd place medal) in my age group (30-39) out of 13, and 12th out of 141 in the field (no walkers included). See Overall results & Men's results.
Added: My previous PR was 21:41 (6'59" / mile). Interesting to see my 5k PRs over time.
For my recovery run: Let's just say that Kao Pad Gra Prow (extra spicy) from Thai Siam is not a good idea the night before a race.