Complex sentence: The 2009 Horned Frogs became the second "BCS Buster" from the Mountain West Conference (and the fourth, overall) and seriously threatened to "bust into" the 2010 BCS National Championship Game.
Split into simpler sentences: The 2009 Horned Frogs became the second "BCS Buster" from the Mountain West Conference (and the fourth, overall). For much of the season, they were a serious threat to "crash" the 2010 BCS National Championship Game.