Found with: Quellx, Clodbuster2, Mtut, Worthy Squire, Knight-Errant, The Night Fox, Art Vandalay, Baldin' Eagle, Dr Jay, RootieSart, The Westie Walkers, Peanuts Parents, Princess Daisies, Mr Morty, Pirate Piggy,  GoblinCamper2004. and Brick Master.
(17) Jan. 15, 2011

A Short, Big, "Bowl"ing Cache

Challenge of the Century: Collaboration

Found with SuperTBone
(1) on Dec. 31, 2010

Cowboy Kokopelli

Found with Jac0b, Kristie!, Resident Evil 5, Brady!!!, T-Y, and Tinkerbelle.
(6) on Dec. 28, 2010

DIE CAST CACHE

Found with WordGirl77, Adraval, and BirdPhish.
(3) on Dec. 1, 2010

Fort Heber Northeast Corner #1

Found with AilshiePadawans and MoonStruckStar
(2) on Dec 4, 2010

Garth's Lost Mojo

Found with Rerb, Goatter, Lovereddesert, Hyperheidi, TinManUT, and daphm
(5) Found May 16, 2011

Next To The Last

S.S.I. Grandkids Cache (Puzzle/Traditional)

Found with BMars 7391, FireElemental, PlumNuts, adam_w, and running wolftech.
(5) Found 2-29-12

Sue She Yes

The Last

Found with WyFy and Team Wilson4
(2) Found 3-2-12

The Wagon Wheel

A list of caches I've found with other people since 12/1/10.

Only the first cache found with each other user is listed.

JMA's list for Challenge of the Century: Collaboration.list-details-1ub8b9x{text-transform:uppercase;font-size:12px;}@media screen and (min-width: 600px){.list-details-1ub8b9x{font-size:1.25rem;}}.list-details-1ub8b9x.shareable{color:#87705a;}.list-details-1ub8b9x.public{color:#00b265;}Public

JMA's list for Challenge of the Century: CollaborationPublic