Easter eggs (Origins)

There are a several Easter eggs in Dragon Age: Origins and this article contains detailed information regarding these Easter Eggs.

Baldur's Gate References

 * When transitioning from one location to a next, a window will appear and ask if you wish to, "Gather your party and venture forth?" This is an obvious reference to Baldur's Gate I and II, when your player character attempted to leave an area without their companions.
 * A loading screen tip reads, "When all else fails, go for the eyes!" This is a reference to the famous Baldur's Gate characters, Minsc and Boo.
 * After visiting a female prostitute in Denerim somtimes they will utter "Hey Sexy! Do you want to take a look at my ditties?" The same phrase is uttered by the prostitutes in Amn.
 * When you get Dog to dig for treasure in the area where you first meet him (assuming you are not a Human Noble) he fill find a pair of old pantaloons that could have once been silver or gold. This is a reference to the golden, silver, and bronze pantaloons that could be collected in Baldur's Gate 1, Baldur's Gate 2, and Baldur's Gate: The Throne of Bhaal, respectively.
 * In one of the Denerim taverns, there is a red robed woman named Edwina. This is a reference to Edwin, from Baldur's Gate 2, and his rather unfortunate "transformation".
 * One of the codex entries mentions a powerful enemy named Gax'Kang. This is a reference to the demi-lich Kanggax, found in Amn in Baldurs Gate 2.

Mass Effect References

 * A character named Sarel at the Dalish Camp will recite a poem for you if you ask about the history of the Dalish Elves. This is a reference to Mass Effect's companion, Ashley, who was also voiced by Kimberly Brooks and had a penchant for reciting poetry. The voice of the assistant to the Dalish Elven keeper  of knowlege also uses the same voice as Ashley in Mass Effect.
 * In one of the game's Codex entries there is a reference to BioWare game Mass Effect and its slow elevator rides.
 * In one of the notes found in Orzammar, there is is reference to a dwarf hero by the name of Shepard, the last name of the main character in Mass Effect.
 * The moon used for this game is the planet in Mass Effect that was damaged by what is said to be a massive and ancient mass-acceleration weapon. Only it has been made blue rather than orange.  The first time you are able to see it is in the Battle at Ostegar.

Miscellaneous

 * During a Random Encounter, an old human couple, one male, one female, can be seen, and a smoldering crater can be seen. The male human says "It's a boy, Martha! Ten fingers, ten toes! The maker's answered our prayers!" This is obviously a superman easter egg. The ore recovered from the meteor crater can also be crafted by certain smiths into a powerful one-handed or two-handed sword, Starfang.
 * There is a book of Dwarven poetry found in the Denerim markets with a poem extremely similar to "Green Eggs and Ham" except it is about "Nugs and Mush" with words like shrugs and chugs, bugs and rugs. The funny part is the poem was written by Paragon Seuess.  It's most obviously a reference to Dr. Seuess.
 * At the waterside in Redcliffe there is a sign saying "No Swimming". This may be a reference to the request that some players made for the game to feature swimming. This is, of course, a ridiculous logical fallacy.
 * If your cunning level is at least 2 and you're using the "experienced" or "wise" voice set, your character will remark "Warden sense tingling" when he spots enemies. This is a reference to spiderman's spider sense.
 * (unconfirmed) Supposedly if you name your Hound Boo, your character will yell for him to go for the eyes.
 * Oren Cousland says that he will one day wield the "sword of truthiness" which is a double reference to the "Sword of Truth" novels and to political satirist Stephen Colbert who is credited with coining the word "truthiness".
 * If you send your dog out to retrieve an item he may return with a cake, one of the possible responses is a refusel to eat the found cake. This sequence of events is a reference to a penny arcade comic.
 * Upon unlocking the door to free Anora who is dressed in armor. Your character can comment "Aren't you a little short for a guard?" A reference to Star Wars: A New Hope upon Leia seeing Luke Skywalker.
 * After killing a group of Templars in the Lothering tavern, a possible conversation option with the barkeep is "Sorry about the mess." This is another nod to Star Wars, in which Han delivers the same line to the bartender in the Mos Eisley cantina.
 * When Shale is selected he will sometimes shout, "stop poking me!" A reference to a common joke in the Warcraft series. If Morrigan and Zevran are in the party together, Morrigan will also utter this phrase regularly if Zevran (player controlled) runs into her.
 * In Haven behind the house to the right of the guard at the entrance is a graveyard with various sayings on the tombstones
 * On one of those is written "T.O. Hanoi. Unloved, unmourned". A reference to the Tower of Hanoi puzzle which was used in Mass Effect and Jade Empire.
 * If you speak with Sten at the end-game celebration, he mentions he thought there would be cake and that "The cake is a lie." This is a clear reference to the game Portal.
 * At the Lake Calenhad Docks, near the Tavern, can one overhear a conversation between two Mages who talk about how all they see is just a dream and only imagined by some 'cosmic greater Beings' . One of them then remarks that he can't imagine anyone getting any enjoyment imagining him and his boils.
 * (unconfirmed) The name of the dwarf city (Orzammar) is a reference to the Orc city in World of warcraft called Orgrimmar. It should be noted that because two fictional names are similar they are not necessarily related.
 * A (dark) hero by the name of Cormic is mentioned several times in the Codex and dialogue. This may be a reference to the Neverwinter city marshall in Neverwinter Nights 2 named Cormick.
 * In the Gauntlet Ealisay asks what a lark could carry but a man not. One of the possible Answers is "A coconut", which is clearly a reference to Monty Python and the Holy Grail.
 * During a random encounter, the player is asked to pull an axe, "Axameter," from a stump. If the player is successful, he is declared the future king of Thedas, at which point several other onlookers will declare that to be a stupid method for determining a ruler. This is a reference to the legend of King Arthur, who pulled a sword from a stone, an act which only the true heir to the throne could perform. It is also a reference to Monty Python and the Holy Grail, where finding a sword is decided to be a stupid way to choose a ruler.
 * Your character may find a ring called, "The Harvest Festival Ring" which is a nod to the game, Neverwinter Nights 2.
 * As the game progresses you can find several characters that share the same name as Neverwinter Nights 2 characters such as Khelgar, Moire, Casavir and Cormick.
 * Shale makes many references to humans being, "squishy." This is a reference to the Knights of the Old Republic character, HK-47, who was famous for referring to, "meatbags" with that description.
 * There is a book you can read in your codex entitled "Adventures of the Black Fox" that is based on Robin Hood. Lord Remi Vascal is a nobleman-turned-rogue who protects the poor from corrupt lords with his team of traveling adventurers.  "Foiling tax collectors" is one of his favorite pastimes, and the book has this to say about his crosses with death: "In each situation, Remi escaped death at the last moment, foiled the evil-doer, and improved life for the poor and downtrodden."
 * During the succession crisis in Orzammar, you will come across two criers - one for Prince Bhelen, one for Lord Harrowmont. Should you support Harrowmont for the succession, and Harrowmont becomes king, the Harrowmont crier may say this as you pass: "News of the hour! Lord Bhelen attacks the Assembly and is ignominiously slain! Epic failed!" A reference to the internet phrase "epic fail," wherein a person or group fails so spectacularly it can only be described this way. For example, Leeroy Jenkins in World of Warcraft. (Epic fail is sometimes described by tabletop RPG players as "rolling a one.")
 * The quest Correspondence Interruptus is a play on the words coitus interruptus, which is a method of contraception otherwise known as the "pull-out" method.
 * A possible random encounter arrives the player at a small abandoned camp with two dead bodies and a Shade ambush. A note on one of the corpses reads, "Why, oh why didn't we just take the flying eagles?" This is a reference to Lord of the Rings.