If you play sports a lot or competively then most likely you stay active and are in at least decent shape. I'm going to give a list of certain exercises you should do to better your performance in your sport of choice. 
Football: If you play football you need lots of lower and upper body strength. Squats, dead lifts, and bench presses should be the staple of your workout routines. Squats are great for strengthening the legs and tremendously increase your over all power that you need to make tackles, blocks etc. Dead lifts are also very great for building over all strength. Dead lifts will help tremendously with pulling power and grip strength. Bench presses are obviously the best over all upper body strength builder. You need strong shoulders and chest as well when trying to tackle, resist being tackled, or to make a great block. 

Excellent post!  I would like throw in either Power clean or hang clean. It works Shoulders and triceps but it also increases and gives you explosion which is also critical in the game of football.

For sure bro! I was just giving the staple exercises. 

And also don't forget about training your abs!! They are like the foundation of all your upperbody. They can really keep you safe from injuries. =)

Yeah those football players really have to have a strong base foundation, and that is LEGS. Well said

Hey fellow Hermanites!
 I play Baseball, and have come to learn over the years of playing that training for your sport specifically is actually better than training as if you play every sport know to existance. The reason im sharing this is because I have alot of friends who play a sport but train as if they were getting ready for every sport, and within the first few games, they always get hurt, but I have yet to get hurt. I train as hard as I can and I make sure that if im in pain that I rest, but I never actually rest. If my arms are sore, my legs arent. If my legs and arms are sore, my forearms arent. Catch my drift, there is always room to grow no matter what. I've come to understand that squats definently help no matter how much you dont want to do those workouts, they benefit in the long run. Thank You Scott for your great determination and untouchable hard work! and keep pushing forward!

What rep ranges should atheletes train in?

Depends on the sport. If the focus in your sport is muscle/strength gain or explosive power (i.e. throwing, powerlifting, strength athletics) I like keeping ranges between 1-5 reps per set for 3-5 sets. If your sport requires you to have great conditioning, working in higher rep ranges to increase your muscle endurance doesn't hurt either, so between 6-10 reps.

1th .... My Basketball Team guys really hated Burpees..... but with a great workout of Burpee, Plank, squat on bosu, box jump, explosive lounge they have seen excellent results.....  and now this is their "daily bread" 

Let's not forget LATERAL MOVEMENTS like side shuffling.  Too often we forget to train our lateral movements and end up with rolled / sprained ankles!  Not good!

Do any of you guys know any good exercises for a rugby player trying to get his strength and power up?

You should try a 5X5 program with Squats, Bench, and Deadlifts.

Perfect for building STRENGTH!

For Hockey players out there:

anything like snatches, cleans deadlifts and such are awesome! If you a hard gainer like me dont worry, you are allowed to do "body building" exercises. Just make sure you do have a balance with "power lifts" and "muscle gain lifts" (i.e tempo, number of reps. Scott posted a video recently about this stuff). Oh and lateral movements are crutial for quick starts and explosivness out of turns.

My cousin started training with me a few months ago. He plays hockey and I definitely have him doing explosive plyos and lateral movements. Great advice brotha!

Absolutely!!! Side Shuffling are one of the basic fundamentals of defense!!! And ALL my teams work hard with the defensive Drills!

This is great for prevent sprains

https://www.youtube.com/watch?v=Xvw3eGriXL8

As a football player myself, i do agree that these exercises should be the core lifts in your rutine. However, you should also put in things like the power clean, front squat, and other accesory/position specific movements to help out your performance. if you have one, a Jammer is one of the best machines for any football player.