Dave Castro surprised everyone by putting up 18.5 to a community vote and then made it even crazier by announcing three of the gnarliest Open workouts of all time as the options: 11.6, 13.5, or 14.2.

11.6

Complete as many reps as possible in 7 minutes of:
3 thrusters
3 chest-to-bar pull-ups
6 thrusters
6 chest-to-bar pull-ups
9 thrusters
9 chest-to-bar pull-ups
12 thrusters
12 chest-to-bar pull-ups
15 thrusters
15 chest-to-bar pull-ups
18 thrusters
18 chest-to-bar pull-ups

This is a timed workout. If you complete the round of 18, go on to 21. If you complete 21, go on to 24, etc.

Men use 100 lb.
Women use 65 lb.

13.5

Complete as many rounds and reps as possible in 4 minutes of:
15 thrusters
15 chest-to-bar pull-ups

If 90 reps (3 rounds) are completed in under 4 minutes, time extends to 8 minutes.

If 180 reps (6 rounds) are completed in under 8 minutes, time extends to 12 minutes.

If 270 reps (9 rounds) are completed in under 12 minutes, time extends to 16 minutes.

Etc.

Men use 100 lb.
Women use 65 lb.

14.2

Every 3 minutes for as long as possible, complete:
From 0:00-3:00
   2 rounds of:
   10 overhead squats
   10 chest-to-bar pull-ups
From 3:00-6:00
   2 rounds of:
   12 overhead squats
   12 chest-to-bar pull-ups
From 6:00-9:00
   2 rounds of:
   14 overhead squats
   14 chest-to-bar pull-ups
Etc. until you fail to complete both rounds

M 95 lb.  F 65 lb.

As of this post, 11.6 is the lead closely followed by 14.2. But 13.5 is by far the best of these workouts and should be the one which is tested. Not only was it one of the most exciting live Open match ups ever, it's also probably one of the best examples of grit and mental fortitude for a workout, even more than 14.2. 

I can't believe I'm actually saying it, but I agree with Castro: it should be 13.5. Even better if it's with dumbbells.