I acquired a large lot of mid century slides last spring that I've enjoyed occasionally browsing through. The family appears to be from the Puyallup area and were avid fishermen. They took lots of beautiful color slides of vacations, parades, holidays and family gatherings.
***UPDATED SHORTLY AFTER POSTING - Stadium Identified***
Seven of the slides appear to be a football halftime show featuring a marching band at Rogers Field in Pullman. It took a couple people helping me out to confirm this was WSU which was my guess because of the color of the uniforms, what appears to be a W formation and another slide I came across of a young man wearing a WSU t-shirt. Cougars played in Joe Albi Stadium in Spokane and on campus at Rogers' Field in Pullman. The "then" photo here of Joe Albi Stadium shows a double deck of stands about the same era as these slides. The "then" photo here of Rogers' Field shows a similar tree line and angled wall between the stands.
"MAD" (representing the colors of University of Oregon?)
"MYSTERY" - Yep, it's a mystery . . .
This looks like a rose to me which of course makes me think of the Rose Bowl. WSU had a great season in 1958 but did not play in the 1959 Rosebowl.
Washington State University t-shirt.