The Tree Bowl is upon us.In one of the more intriguing matchups of Week 3, coach Jim Harbaugh and his San Francisco 49ers will host quarterback Andrew Luck and the Indianapolis Colts -- and their new running back Trent Richardson.This is a homecoming for Luck and a reunion for both men. Luck played for Harbaugh at nearby Stanford. They were the toast of college football, and Harbaugh played it into a job with the 49ers after the 2010 season. Luck stayed on The Farm another year and had a brilliant rookie season last year.