Keep the car clean

With soccer, football, cross country, and other fall sports at hand, our cars sometime need help staying mud-free.
A couple of ideas that have worked for me are:
Keep a plastic dish pan in the trunk or back of the car.  I got mine at Walmart in the kitchen aisle for under $3.00.  The muddy cleats can go in it. 
I got a yard of marine carpet at Econo Sales.  It's 72" wide and I cut it down the middle so I had 2 pieces 18X72.  One of the pieces fit across the floor in the back protecting the carpet.  Cut the other piece in half, one for each side of the front keeping it clean.  The marine carpet won't mildew when it gets wet. 
A third item I keep in my car is a piece of ripstop nylon.  When the kids have muddy behinds, I put the ripstop on the seat before they get in.  It folds us easily and just hose down and hang dry.