Last minute campsites in Wisconsin?

I take my family on the weekend camping on Memorial Day. I know it'sa little late to make a reservation, as almost everything is booked. Does anyone know if a family oriented camp in Wisconsin or northern Illinois sites that may still be open? Thanks in advance for all your answers!

Camps did you try Google? + Northern Illinois and Wisconsin camping + There are plenty of places I've been in the areas accurate than you talk. Unfortunately I can not remember any of their names. Come back if I think of something.

Camping in Northern Wisconsin Chequamegon Nicolet National Forest May 2009