is a Sacramento area based Parkour/Freerunning group. They welcome and encourage practitioners of any age/skill level/practice/discipline to practice with them at any Parkour jam they may have. They welcome anyone willing to join the Parkour movement.
See their facebook group for more info.
There is a group in Davis that trains a few days a week, mostly on the UCD campus. Their Facebook page can be found here: Davis Agility Nerds
and their YouTube playlist can be viewed here: Davis Agility Nerds (Parkour)
They often visit the San Francisco bay area to meet and train with the Parkour communities, and they are very good at getting beginners to free lessons and coaching.