CO had a crappy scandal against Ken Buck running for senate on his remarks with women which got rid of his lead before the final days of election. He was neck and neck with Michael Bennet.
Scott McInnis plagerized an article from a 20 year old Hasan Family Foundation which made him drop out of the race for the GOP. He was ahead in the polls running as governor in 2010 before dropping out. Also Tom Tancredo was running as a 3rd party candidate against Hickenlooper and Dan Maes with a couple months too late. He didn't get enough recognition and votes.
I thought McGinnis lost in the Republican Primary to Maes 51-49% and didn't drop out of the race. i I remember Maes being a mess of a candidate after he won the primary. The National GOP(RGA) wouldn't throw any money his way.