[Husker] Colorado Extra Poing

[C Jolly]

We were driving when Colorado scored the last touchdown.  My aunt called 
to celebrate the win since there
was no more time on the clock and I didn't hear how the game finished.  
I surprised to hear that the game was 28-20 instead of 28-21.  I thought 
that the extra point was played for after a touchdown in regulation 
play. If they don't try for the extra point, that could shift a lot of 
money being bet depending on what the line was.  What is the rule for 
kicking extra points if the last play of the the game in regulation 
results in a touchdown?