15. Also in Nagrand, there is a nursery managed by a Female Troll that has many different children (including Human, Orc, Night Elf). There is an... interesting playground and a chilling hint about what the children are for...
16. In Northern Elwynn, there is a house with a large group of sheep outside, with one mechanical one. Kill the mechanical sheep, and a gnome will run out, yell at you and go back inside.
17. Also in Northern Elwynn, there is a small campsite near a waterfall. Good for RP.
18. In the most southeastern part of the Dun Morogh, there is a house with a dock next to the sea with 2 Booty Bay Bruisers standing on it. There is a sign that refers to the house as Newman's Landing
19. In the northern mountains west of Gnomeregan, there is an abandoned encampment that is being run over with a few black bears. Up in a nearby tree, are 2 dwarven NPC brothers that have an argument over whose fault it is that they attracted bears. 2 bears are trying to climb the tree to get to them, and another bear rummages through the tent, while 2 bear cubs watch.
20. In the Caverns of Time: Escape from Durnholde (Old Hillsbrad) instance, you can head to Southshore and see many different NPCs as they were back in that day, including Kel'thuzad, Tirion Fordring, and the Morgraines. They will converse, often talking about things that they end up doing in WoW (such as Kel'thuzad discussing necromancy). There is also a vendor that sells Rumsey Rum Black Label, and another travelling vendor that sells the gear that many classes start with.
21. On Ironforge mountain, there are lots of dwarf NPCs sledding. They are friendly to Horde. Some of them even carry around makeshift sleds. Every so often, one of the sledders slides down the hill on their sleds, lands in a snowpile near Chillbreeze Valley, /cheers, and then drags their sled back to the top of the hill. There is also a small path that leads to a cave where the sledders have a campfire and (of course) loots of booze.
22. In the mountains between the Twilight Highlands, Loch Modan and Badlands, there is a section that is still logged as The Forbidding Sea. So you can be in an ocean zone, in the middle of a mountain.
23. Also on the same mountain, are "Coldmine Explorer" NPCs (flagged Alliance) who drop AV drops (Stormpike Flesh, etc) when killed.
24. In the Stormwind barber shop's upstairs room, there are 4 small corpses underneath a floorboard. This is apparently a reference to Sweeny Todd
25. In Netherstorm every so often a Fel Reaver called Negatron will attack Area 52. This is a Transformers reference
26. The Tol Barad quest "Magnets How do they Work" is named after an ICP song, and a popular meme.
There are also many memorials in the game
-In Mulgore, there is a quest given by a Tauren in Bloodhoof Village that was created by a child via Make a Wish. link: http://www.wowpedia.org/Ahab_Wheathoof
-In Hillsbrad, there is a dwarf kneeling next to the grave of his friend, Anthony Ray Stark. Anthony Ray Stark was the friend of a WoW developer.
-In the Barrens, there is a Spirit Healer on a mountain near a memorial for Michael Koiter, who died when WoW was being developed.
-In Orgrimmar, there is a secret memorial inside of a rock for WKM. Reportedly unreachable after a hotfix a few weeks ago (conformation?)
-There is a quest in Stormwind where you have to take a poem to Caylee Dak, a Night Elf Hunter in Shattrath (who has nice gear for a NPC). It is an in-game memorial to Dak Krause, who died of leukemia in 2007.