There are event weekends in North Florida every month at the Florida Motoplex in Madison county. I have attended a few of these events and they are fun for the whole family. This months Feature weekend starts on April 18, 2008 and ends April 20th . There is free camping and it only costs 20$ for the whole weekend.
They have a website the address is Florida ATV - Welcome to the official home of the Motoplex there are many picture on the site as well as info about it. There are Mud trails creek and lakes, 1 way trails, peewee MX track, Adult Mx track and drag strip.