Summer is the time for the famous Ellensburg Rodeo and Fair. There are many opportunities to see more of Washington State. You can go on a UESL trip or an International Students' Association trip. Or you can travel yourself to various places. Yakima is only 45 minutes south of Ellensburg.
Famous musicians play concerts here all summer long.
To find really big city life and entertainment you only need to travel to the west for two hours to arrive in Seattle or three hours to the east to arrive in Spokane. If you do not have a car, you can always take the Greyhound Bus.