Follow the approach on the main page under Getting There to reach the river-face of the formation. Once near the base, look for the characteristic roof/arch (~40 feet off the ground) that marks the beginning of Calamity Jam route (5.10c). Crack of Infinity (5.10b) as well as its 5.10a variation start in the small dihedral below the right side of the roof/arch. Route starts five or so feet left of the start of Friday's Jinx - the line in this photo here.
The route reaches the top of the formation (though it does not top out on any of the summits of the Four Horsemen) in three short pitches. The description here is given for the 10a pitch one variation (I'll add in the 10b "standard" here as well once I've done it). The highlight of the route is the great (but too short) handcrack of pitch 2 (5.8). Roughly speaking, the route connects the starting and ending points of the white curve in this photo by a straight line. Pitch one shares the belay with Friday's Jinx. The route is a soft 10a IMHO - a handful of 10a moves separated by good stances (with good pro).
Pitch 1 (Variation): 5.10a, 70 feet. Climb up the obvious dihedral below the right side base of the distinct roof/arch (that marks the beginning of Calamity Jam) about 15 feet. Mantle onto a good stance on the right. For the standard route, stay in the dihedral and pull the roof directly above (acc. to book). Follow a right-leaning crack in shallow dihedral (exiting the dihedral is the crux). Belay on a good ledge with two bolts (same as top of P1 of Friday's Jinx).
Pitch 2: 5.8, 90 feet. Move up the dihedral directly above the belay (same start as Friday's Jinx) for about 15 feet. Pick up the great handrack and follow it up and left (away from dihedral). Beginning of crack involves pulling over a minor bulge (crux, 5.8). As the angle kicks back near the top, traverse left ~10 feet and belay on a sloping ledge (gear) below a short dihedral.
Pitch 3: 5.9, 50 feet. Move up the 25-foot dihedral (5.9). Mantle and move right over easy terrain. Note that there's a doubly bolted rap station directly above the dihedral. You can stop here or walk right and "jump" into a chimney (same as top of Friday's Jinx) where the hiking trail begins (one bolt).
Descent: Rap the route from the bolted anchor above the 5.9 dihedral on P3 (either one double rope or two single rope raps - using bolts atop P1). Or you can walk around the Fourth Horseman formation (walk back and left) and rap Pack Animal (one double rope rap or two single). Or you can also walk all the way to top of Cinamon Slab route (Dihedrals) and rap that (see Friday's Jinx and Pack Animal descent descriptions).
Mid-sized rack to about 3.5 inches. Pitch one takes small cams and nuts (<1 inch). Pitch two handcrack eats up #2 - #3 Camalots. Third pitch (as well as the belay) might take some larger gear (#4 Camalot) but you can get by with smaller gear (hint: look at the thin left crack on P3).
If you have information about this route that doesn't pertain to any of the other sections, please add it here.