The Twin Cities River Rats are back in action, waterskiing on the Mississippi River nearly every Thursday evening through Aug. 31, with some Tuesdays, Wednesday and Fridays thrown in.  The "stage" is south of the Broadway Bridge. 6:30 pm Pre-Show, 7 pm Main Show, until Aug. 15, when the Main Show moves up to 6:45. See http://tcriverrats.com/schedule for dates and show times. Free.