Two fantastic compilations of Bitcoin history are available at the HistoryOfBitcoin.org and igotbitcoin.com/milestones sites.

January 2 Tonal Bitcoin units standardized.

January 8 History of Bitcoin page (this page) created after replicating from original Bitcoin History page on Bitcoin.org.

Bitcoin Pooled Mining reached a total of 10,000 Mhash/s

January 27 Largest numeric value ever traded for bitcoins thus far occurred on this date. Three currency bills from Zimbabwe, known as Zimdollars, were traded on #bitcoin-otc at the rate of 4 BTC for each of the one-hundred trillion dollar ($100,000,000,000,000) Zimbabwe notes[6]

January 28 Block 105000 was generated. This means that 5.25 million bitcoins have been generated, which is just over one-quarter of the eventual total of nearly 21 million.

February 9 Bitcoin reached parity with the US dollar, touching $1 per BTC at MtGox.

February 10 Bitcoin.org website struggles to handle traffic resulting from mentions on Slashdot[7], Hacker News and Twitter following the news that parity had been reached.

February 14 A vehicle was, for the first time, offered in exchange for a certain number of bitcoins[8].

March 1 MagicalTux buys mtgox.com from its founder Jed McCaleb

March 6 Total Bitcoin network computation speed for a short time reached a new high of almost 900Ghash/sec, dropping to 500Ghash/sec soon after. Some speculate that this was due to some supercomputer or bot-net that joined the network (mystery miner).

March 18 BTC/USD exchange rate reaches a 6-week low point at almost $0.70/BTC, after what appeared to be a short burst of, possibly automated, BTC sales at progressively lower prices. BTC price had been declining since the February 9 high.

March 22 WeUseCoins releases the viral video What Is Bitcoin? which has had more than 6.4 million views.

March 25 Difficulty decreased nearly 10%. A decrease has only occurred once before, and this decrease of nearly 10% was the largest.

March 27 The first market for exchanging bitcoins to and from the British Pound Sterling BTC/GBP, Britcoin, opens.

March 31 The first market for exchanging bitcoins to and from Brazilian Reals, Bitcoin Brazil, opens.

April 5 The first market for exchanging bitcoins to and from the Polish złoty, BitMarket.eu, opens.

April 12 First bitcoin put option contract sold via the #bitcoin-otc market.

April 16 TIME does an article on Bitcoin.

April 23 BTC/USD exchange rate reaches and passes parity with the Euro (EUR) on MtGox exchange.

BTC/USD exchange rate reaches and passes parity with the British Sterling Pound (GBP) on MtGox exchange.

Value of the Bitcoin money stock at current exchange rate passes $10 million USD threshold.

April 27 VirWoX opens first market to trade bitcoins against a virtual currency on BTC/SL (Second Life Lindens) exchange.

April 30 The generation difficulty passed 100,000.

June 2 The exchange rate at MtGox touched 10 USD per BTC.

June 3 Tonal Bitcoin reached parity with the US cent, touching 1¢ per TBC at Bitcoin Market.

June 8 The MtGox exchange rate peaked at 31.91 USD, at a "market capitalization" of about $206 M [1].

June 12 The MtGox exchange rate briefly dropped to near 10 USD four days after the peak, in its largest percentage price retreat to date.

June 13 Forum user allinvain claimed to have had 25,000 BTC stolen from his Bitcoin wallet (approx. USD equivalent $375,000).

June 19 The MtGox database was compromised and the user table was leaked, containing details of 60,000 usernames, email addresses and password hashes, some of which were overly simple to brute force passwords.

June 19 Someone was able to access an admin account at MtGox and issue sell orders for hundreds of thousands of fake bitcoins, forcing the MtGox price down from $17.51 per bitcoin to $0.01. MtGox announced that these trades would be reversed. Trading was halted at MtGox for 7 days (and also briefly at TradeHill and Britcoin while their security was reviewed).

June 19 Some of the users on the leaked MtGox database had used the same username at MyBitcoin and had their passwords hacked. About 600 of them had their balance stolen from their MyBitcoin accounts. One user lost over 2000 BTC.

June 20 The EFF announced that it was no longer accepting Bitcoin donations due to legal uncertainties.

June 24 The generation difficulty passed 1,000,000 with Block 133056.

July 19 "Let it go on record that at 4:05pm CET [19 July 2011], my manager Tadek was the first person in the world to receive [testnet] Bitcoins via NFC ;)" - Mike Hearn

July 22 BitCoins Mobile, the first Bitcoin application for iPad was released by Intervex Digital.

July 26 Room77 becomes the first brick-and-mortar business (bar) to accept Bitcoin as a means of payment.

July 30 Tribute to Len Sassaman included in the blockchain[9].

August 20 First Bitcoin Conference and World Expo held, in NYC.[10]

August 23 P2Pool, the first P2P decentralized pool, mines its first Bitcoin mainnet block (Block 142,312).

August 30 Difficulty adjustment at block 143,136 marks the first back-to-back drop.

November 15 First CVE (CVE-2011-4447) assigned to a Bitcoin client exploit.

November 25 First European Bitcoin Conference in Prague, Czech Rep.[11]