Just left of the crack (Betty Cracker 5.9) this route starts easily enough but soon after the moves and holds get thin.
Vertical route with crimpy holds on that super grippy dark grey rock. It's nice.
Location
While walking in from the main trail you'll come across a large low angle boulder (sinker 5.5)just above the wash bottom. Directly in front of the boulder is a courtyard that gets early morning shade year round. Third route from the right on the south facing wall.
By Andrew Ryder From: Flagstaff, AZ Dec 2, 2007 rating: 5.10d
The guidebook calls this route "sustained" but I found it to be anything but. The crux was short, more based upon solid technique than strength, and was followed by a nearly no-hands rest and a bunch of really positive holds to the top. Didn't really seem 11.
That said, this is a good 10/10+ with some fun moves and great holds.
Andrew, I agree the crux is short but it's still probably a series of .11 moves to get past it. Small pockets and somewhat technical on vertical rock. It only takes one move of .11 to make the grade. The upper section eases but the crux still packs a punch.
By Andrew Ryder From: Flagstaff, AZ Aug 10, 2008 rating: 5.10d
Maybe this route just fit my style, I dunno. To me it felt about the same as Genesis which seems like a good benchmark for 10+ at Jacks. Not that it matters too much, this is a fun route with good moves on solid rock and that's what counts.
If you really want to tick a 5.11A, this is the route to do! Unlike the poster above, I found the nature of this route to be the opposite of Genesis. Genesis is pumpy, gently overhanging climbing while Mental Block Party offers almost pure vertical climbing with plenty of rests; it really shouldn't pump you out at all. I found the 5.9 one climb over to the right to be pumpier.