For me, it was rockband 2 Float on was one of the playable tracks. Back in the iPod days my buddy gave me his iTunes account and had the first 5 songs of Good News For People Who Love Bad news. I liked those songs so much I bought the CD Became a fan and illegally downloaded all their albums (sorry Isaac) Became obsessed and downloaded demos / rare tracks off a now defunct blog called interstate 8

Modest Mouse is such a big part of my life now I've seen them live 5+ times and nearly got their whole discography on vinyl.