What are the rules of that field goal thing...?

In one of the cardinals games this year, there was only like 4 seconds in the half left. The cardinals had the ball near midfield, and they set up in kickoff formation, to kick like a 70 yard field goal. I don't think they actually went through with this, but i really don't understand. Why don't teams do this everytime? Are there certain rules to this?