1. Barcelona vs Real Madrid

The spectacle that is El Clasico. Millions, even billions, gather at least twice a year to watch the best of La Liga go at it. It's safe to say that is never disappoints... well, unless you're on the losing side.

2. Nadal v Djokovic

These two have faced each other 52 times, with Djokovic having the slight advantage, having won 27 and Nadal winning 25. That statistic alone should paint the picture of just how competitive and promising it is when these two play each other. If that's not enough, their matches have more often than not gone to five sets. If THAT'S not enough, they hold the record for longest Grand Slam final ever -- a whopping 5 hours and 53 minutes at the 2012 Australian Open.

3. UGA v GA Tech

MAYBE not one of the greatest rivalries, but I go to UGA and am very, very biased (for my dawgs, tho). We first played each other in 1893, and the clean, old-fashioned hate ain't letting up anytime soon!

4. Man City v Man U

This one is as old and as good as it gets. The best of the best of English football play each other at least twice, and it's always a show. In an extremely interesting turn of events, the two men, Jose Mourinho and Pep Guardiola, that had been the managers of Real Madrid and Barcelona at the same time are now the coaches for Manchester United and Manchester City, respectively.

5. Cavs v Golden State

WELL, this is not a surprise. These two teams have faced each other in the last four NBA finals. Golden State holds the advantage at 3-1. This rivalry might turn into a renewed Golden State v Lakers rivalry with LeBron's controversial move to the Lakers this summer. Keep an eye out, people!