The Springbike calendar is a good resource for weekly rides.
Racing info for Missouri: MOBRA

Jump on the Highway, head North and hit the dirt in Warsaw. The next found of UFD mountain bike racing:

Down and Dirty June 9th.

The Waffle Summer Series kicks off on May 7th. A total of seven events presented by the Mercy-Kuat team at Fellows Lake. Great organized training (and yes, it feels just like a full blown race) on a rolling 11 mile circuit. Yellow jerseys for A and B race 'leaders'. Don't miss.

UFD Racing comes to Sac River on April 21st with another edition of the OMBA Caramba. 

Fantastic (and challenging trails) with XC and Marathon classes. RESULTS

Just up the road in Warsaw, MO: Feel The Burn endurance mountain bike race on April 6th and 7th includes a dirt crit and kids events. Def good times.

The Frozen Waffles Training Race is back on 3/3/13. Great circuit, ideal for beginners. Check out the flyer which includes course preview.

Hop up the road (hopefully we'l have clear pavement) for the kickoff road race in Central Missouri:

Froze Toes Road Race has been moved to March 10th due to Storm Q. Updated flyer

Head North to Warsaw, MO for the kickoff 2013 endurance mountain bike event, Feel The Burn. Two days of racing March 9th and 10th.

You've got to travel a bit for CX racing this year, but St. Louis, KC, and OKC are worth the drive for some excellent events.

The Missouri Cyclocross Champs for 2012 will be held in Jefferson City. Here's the link to the MO USAC schedule.