The Shamrock Series is a series of games that amounts to a marketing ploy by Notre Dame football. It’s been playing off and on since 2009 when Notre Dame played Washington State in San Antonio. The idea is that Notre Dame can play a game for fans around the country to see them play, instead of needing to travel to South Bend. This will expand visibility, and grow Notre Dame’s program.
They also wear strange uniforms, as a way to entice recruits who choose Oregon only for the different uniform combinations. Well, they also want to sell more merchandise, and the Shamrock Series is as good an excuse as any to unveil weird uniforms that can be anywhere from cool to annoying to see Notre Dame wear.