As far as activities - I'm actually getting married out here in August and prepared a google maps for my wedding website of things I think my guests woudl enjoy (most are either family or twenty something year olds, for reference). Here is a link to it - it is coded by color for different activities - eg: yellow=parks/things to see, green = my favorite food and purple for drinking. Orange is Woodinville, which is the wine country so to speak.
https://mapsengine.google.com/map/viewer?hl=en&authuser=0&mid=zKuLbAdsDWtA.k7KrfRdkmWCw
Another thing to note is that UW's campus was designed by the same person that designed ISU's campus (granted there is a little more natural beauty to work with out here), if you are into that sort of thing. UW football is always fun and will be occurring in September as well. Tailgating on boats is a little different than the grass fields of Jack Trice.
That map is awesome, thanks! And thanks to everyone else too. Some great suggestions...