“Blackjack”
aka: "Twenty-One," Benchmark WOD
- For Time
- 20 Push-Ups, 1 Sit-Ups
- 19 Push-Ups, 2 Sit-Ups
- 18 Push-Ups, 3 Sit-Ups
- ...continue this pattern until...
- 2 Push-Ups, 19 Sit-Ups
- 1 Push-Ups, 20 Sit-Ups
Each round totals 21 reps (push-ups descending from 20, sit-ups ascending from 1) for a total of 420 reps in the workout.

We're not able to determine the original source of this workout (if you know, tell us). The oldest mention we've found is from Mad Dawg Fitness (Redwood City, CA, USA), who posted "Blackjack" as their workout of the day for December 14, 2007.