Lake Rathbun is about a 2 hour drive Southeast of Des Moines.  It is also known as Iowa's Ocean as it is the largest lake in Iowa.  It is also a Corp of Engineer's lake.   There are campgrounds on both sides of the Lake.  We stayed at Island View campground.   The campground was decent, but for a Corp campground I expected the facilities to be a litle nicer.  It did have several large swimming beaches which were nice, but you have to watch out for the bird poop from the many seagulls and other birds that hang out on the shoreline.
New to Lake Rathbun, is Honey Creek Resort, which you can see from my picture has a nice indoor water park.  It costs $10/person for the water park.  Two years old and younger are free.  I was disapointed in the height requirement for the waterslide though.  My 5 year old loves the slides, but they would not let her on, and she wasn't even close to meeting the requirement even though she is above average height for her age.
Overall, the experience was decent, but I probably won't be going back anytime soon.  If you have a PWC, then this lake is surly worth visiting.  Please add your comments into my blog if you have been there and have an opion on it.