Hey, My name is KaspQT (Hurrderp) and I've mained rammus for about 100 games now. I've played a couple jungler's now, and Rammus is by far my favourite, he jungles and tanks amazingly! In this guide i'll be telling you how to play a Jungle Rammus, so that you can freeball to victory like I have.

Pro's

Easily one of the hardest champions to take down.
Taunting is a great skill for support, basically a three second stun.
Great AOE damage, allowing you to get many assists (To make you look good of course)
Able to be aggressive and defensive with Powerball

Cons

Does he have any?
no

To start off with I go with cloth armor and 5 health potions, and start jungling. After I finish my ninja tabi I go with a Sunfire and then depending on the team I build differently, if there are alot of casters get a force of nature and a banshee's veil, and don't forget those melee carries! Thornmail rips them apart.

Now that you have those 5 health potions and your cloth armor you can take out that golem!Run to the tower closest to the golem and wait, be sure to have your allies around to help you out and make sure you don't get ganked, at 1:55 the golem spawns so walk over and tear him apart, hitting him with smite when he's low and using a health potion as soon as you start fighting. Be sure to pop your W right away. Once you level get powerball and roll on over to the wolves, being sure to hit them with your Powerball. After the Wolves roll on over to the wraiths and focus the greater wraith. Take out the golems and head up to lizardmen, casting smite on him. Return to base and finish your ninja tabi. By this time you should be level four and ready to gank, be on the lookout for low enemies or good oppurtunities now that you have your taunt.Be sure to keep on jungling later game for the blue buff, because you will run out of mana quickly and the CDR is a great help.

As you've noticed I like to max out Taunt before Powerball, and the reasoning behind that is sure the slowing effect is really nice but being able to taunt the enemy for 3 seconds is a huge help, enabling you to do more damage and your teammates more time to take out the enemy.
Leveling W first for is the most obvious thing to do, it makes you a super tank, allows you to do more damage AND makes you a tower diving king.

I really love my Ghost and Smite, for jungling smite is a neccesity, no question about it. Why Ghost? Ghost allows you to move much faster to be aggressive or defensive, I don't grab flash because it's just a quick teleport away, not very good for helping you reach your teammates when they need your help. I don't take Ignite or Exhaust because ghost is simply much more viable.

If you liked my guide, please let me know, if you didn't... Don't hurt my feelings too bad, I would love to see some criticism and how I can improve my guide, I hope the best of luck for you all, and I hope that you liked my guide!