Ok I'm a little concerned you have started something bad here. Why do you let your wife park in the garage? It sets a bad example. Shame on you.
Most of us have so much stuff neither of us park in the garage!
Ok seriously check this out. http://doorpal.com
You can do the same with a blow up...
I have used the quickcrete mix with great success.
http://quikrete.com/ProductLines/CountertopMixPro.asp
Key here is only use the amount of water as directed. It will be very dry, but this is necessary for it to set properly.