I have found most recently the development of the spread offense to be highly intriguing. Basically, for the past 100 years of football there has been 1 main philosophy: be bigger, stronger, and faster than your opponent. Until the past 25 years or so, every strategy included power as its main ingredient; even the West Coast Offense [The WCO was highly influential in the spread's beginnings, but there is still a difference in the two].
This has changed as of late. A new style of offense has developed very logically named the "Spread Offense" because it does just that. The basic idea of the spread is not to over power the other team, but to isolate one position on the football field and beat it with superior athleticism. Regardless of whether or not there is superior athleticism, the fact that the ball carrier is 1-on-1 and not 1-on-more than 1, is a significant upgrade.
Thus, the whole way offense is thought about has changed. Where before many teams aligned themselves close to the ball before the play started, now teams rely on spacing themselves out in a variety of positions. This spacing is the key to creating mismatches. Once teams are spread out thus creating the 1-on-1 match-ups, there are a variety of ways that teams can take.
Hopefully, a team utilizing the spread offense will find its quick players being guarded by bigger, slower defenders. Because of this, the spread is able to cover up deficiencies that a team may have. It is about individual skill in a 1-on-1 situation. Thus, allowing a less talented team to compete with superior talent. [in my opinion, more small high school football teams should use the spread as opposed to the old-school triple wing power running style. both offenses are attempting to mask the deficiencies of their school's talent pool; just IMHO, the spread is a much more effective strategy.]
The first main way to exploit the spread is with a quick passing attack. We see this in the NFL with the Patriots. Tom Brady usually works with 3 to 5 spread out Wide Receivers. His options are to 1.) look for a linebacker [a slower larger defensive player] matched up with a quicker, faster WR, 2.) throw a short pass [which is the equivalent of an old fashioned running play], or 3.) with all the WR's in movement [thus causing a defense to look for short passes] there might be one able to get open for a deep pass.
The second way to use the spread offense is a power running game. We see this used mostly by the Florida University Gators. They have a massive, brutish Quarterback named Tim Tebow who is more likely to plow over defenders than he is to avoid contact. Thus by spreading out the defense with fast players, causing the defense to spread out in order to defend against them, Tim is able to run against fewer & smaller defenders.
The third way that the spread can be used is a speed running game. This is used by teams like the University of Texas, the West Virginia University Mountaineers, and also the University of Michigan Wolverines. This is a strategy where because the other team is so spread out, the faster quicker quarterback, wide receivers, and running backs are able to use their speed to out maneuver the bigger, slower defensive linemen and linebackers. [often these teams decided to run one way or another simply by reacting to how one player on the field is attacking their offense.]
Already, we're seeing the effects the spread is having on the game of football, as every team in the higher levels of the game has included some elements of this into their gameplan.