Hill climbing, mud crawling, obstacle avoiding, trail running through good ol' Humble, Texas mud. The course is 5K-ish and guaranteed to make you muddy.
There is also a 1 mile Mud Mini for children ages 3-7. This will allow them to run a mile of the race and get muddy if they have no interest in participating in the 5K distance. Children are not allowed to go in the mud unattended>> http://www.mudmaxx.com/mudmaxx/mudmaxx.html