Frank (Ryan Reynolds) is 10 minutes late for a time efficiency speech which inadvertantly alters his entire life.
He finds out his daughter Jesse does not belong to him, but to his best friend Buddy (Stuart Townsend).
He then decides to never decide anything ever again and uses index cards with various options to accomplish everything he always wanted to.
(Fighting, Hockey, Streaking across the ice, buying and riding a motorcycle sans helmet, drinking more, sleeping with Sarah Chalke, etc.)
After nearly killing Buddy in a rage he decides chaos theory is really just a factor of love and that he loves Jesse and his wife Susan (Emily Mortimer) and decides to go back to them.
He then walks his daughter down the aisle with Buddy and Susan and watches her get married.