"Jungle Heimerdinger? Are you crazy?"

First off, Heimerdinger, albeit squishy, can snag blue buff at level one without a leash.
Secondarily, he can gank well. His rockets have the range and his turrets the backup capability. He has stuns and slows, even a blind if the stun fails.
Third, if you think its not a serious thing, get out...

Do not attempt this if you haven't a clue how to work Heimerdinger's turrets or rockets, how his ranges are, and how his damage scales with level.

+ Quick ganks + High gold farm + Turret warding allows safety in the jungle and a teleportation point for a gank on counter-junglers. + Its ****ing Jungle Heimerdinger

SPACE

- Slow in the start - Very unforgiving if you miss that first turret and get aggro on the blue buff. - Extremely squishy, more of a glass cannon jungler. - Naturally slow movement speed, needs boots in his build.

Alright, so we start at blue buff. You have your Meki Pendant, H-28G Evolution Turret, and your potion.
Get to bluebuff as fast as possible and plant a turret where the golem spawns, if not a little bit behind it. This gives you the time to build up another turret while waiting for it to spawn.

Your turret will immediately snag aggro on the Golem, and will actually tank for a long duration. If you are fast enough, you can place another turret before that one hits its minimum and dies. Currently, you have maybe 400 health. A squishy AP carry. If the golem aggro's on you, and with careful use of smite and turrets, you should get out with a minimum of 350 health. Pop your potion, move on to wolves with another turret pocketed. You should be level 2, and now you have your Hextech Micro-Rockets

Continue running through the movements, let the turret take aggro, and rocket them every chance you get. The kills get your mana back with the recent jungle buff update.

Currently, you can easily get first blood on mid or top if you coordinate things just right with your middle or top lane, maybe even bottom.

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Your CH-1 Concussion Grenade gives you ganking capability at level 3.
(running the jungle from bluebuff to golems on bottom will get you the experience to reach level 3, unless there is a Zilean on your team, then it may be wraiths due to his passive, Heightened Learning.)

Run out of the jungle near top or mid, toss your grenade when the lane is ready for a gank, and the enemy is either confused, blinded, and/or stunned if it lands. Run in behind them, drop a turret, and spam hextech micro-rocket until you get your grenade off cooldown.. Rinse and repeat.

When ganking at Level 5, you will have Level 3 H-28G Evolution Turret. This means duo-turrets. Albeit tedious to place correctly, it makes an excellent choke point. Ganks are more likely to be successful from now on, and you may have complete control of any lane you please at level 6 due to your ultimate...

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What people don't understand about Heimerdinger is that his turrets aggro directly on any champion that deals damage to him, no matter what they are targeting before hand. Thus, people who think they can ignore them will drop like a rock.

• UPGRADE!!! as a passive: Cool-down reduction as a passive, more rockets and more grenades. What people don't often know is that his turrets are affected by cool-down reduction in the means of stockpiling.
  A turret generates once every 25 seconds, being reduced with CDR to what I believe to be 19-18 seconds at maximum.
  
• H-28G Evolution Turret: Your turrets currently out will be healed to 100%, this tells us that its for when times get hard for the old 'Dinger. Getting ganked by a smart team will usually mean your turrets are priority. Pop your ulti, they get healed. Furthermore, they are now given a CrowdControl capability much like Ashe's Frost Shot.
  All turrets placed will have this effect during the duration of the Ultimate.
  
• Hextech Micro-Rockets: Bread and butter made into your Ambrosia. Instead of three rockets...Five. That's the whole enemy team. Enemies that know about your rockets prioritizing by distance means they will keep three minions between you and them at any given time, this gives you a new two rocket buffer to work with.
  
• CH-1 Concussion Grenade: Great speed increase, thus a much more accurate grenade. Less compensation is required for a champion's movement.

Archangel's Staff: AP:Mana ratio making it a great late game scaling item. Gives mana for each time you use an ability. Each turret placement, each rocket, each grenade.

Sorcerer's Shoes: Magic Penetration and, of course, movement speed.

Athene's Unholy Grail: New item with godly benefits. Never go OOM again, never need blue-buff again. CDR from your ulti and the grail will hit the cap and thus leave the buff for a more mana hungry teammate.

Will of the Ancients: AP for all of your abilities, spell-vamp for the sustain. Spell-vamp affects your turrets, enjoy yourpenta-kill.

Rabadon's Deathcap: Late-game destruction, mid-game domination. Passive Synergizes well with your Archangel's.

Rylai's Crystal Scepter: Your ulti in an item, free slow, nice amount of health. Use with your ultimate and no one will escape.