There is an event called Darkmoon Faire that appears every two weeks. During the event, you can complete quests for each profession.
The profession quests can only be completed once during each Darkmoon Faire, and will grant 5 skill points.
Table of contents
In-Game Calendar
You can quickly check when the next Darkmoon Faire starts by clicking on the calendar icon on your minimap.
Where is the Darkmoon Faire?
The location of the Faire is on Darkmoon Island. The portals to the Island can be accessed in the following locations:
You can find the portal to the Darkmoon Faire in Mulgore at the base of Thunder Bluff.
Mulgore
You can find the portal to the Darkmoon Faire on the south side of Goldshire in Elwynn Forest.
Elwynn Forest
List of Profession Quests
Some of the quest requires additional items, but all of those items can be bought from vendors, don't buy them from the Auction House.
The nearest vendors to the Darkmoon Faire portals are 
Shadi Mistrunner and 
Tharynn Bouden. You can buy the Moonberry Juice for the Alchemy quest from Kuruk and Innkeeper Farley
- Alchemy - A Fizzy Fusion
- Archaeology - Fun for the Little Ones
- Blacksmithing - Baby Needs Two Pair of Shoes
- Cooking - Putting the Crunch in the Frog
- Enchanting - Putting Trash to Good Use
- Engineering - Talkin' Tonks
- Inscription - Writing the Future
- First aid - Putting the Carnies Back Together Again
- Fishing - Spoilin' for Salty Sea Dogs
- Herbalism - Herbs for Healing
- Jewelcrafting - Keeping the Faire Sparkling
- Leatherworking - Eyes on the Prizes
- Mining - Rearm, Reuse, Recycle
- Skinning - Tan My Hide
- Tailoring - Banners, Banners Everywhere!
These quests can be completed at every faire, so if you take it slowly, you can gain more than +5 skill points. (It seems currently you can only complete the quests every month instead of every two weeks. This might just be an oversight by Blizzard)