People often point out that dates like 12-12-12 only come around once in a century and is "once in a lifetime". Of course EVERY fricken calendar date is likely going to be once in a lifetime, given that life expectancy is less than 100 years. There is nothing particularly remarkable about these inevitable dates that happen every century.
A huge amount of hub-bub was made about 6-6-6, a few years back, especially due to ignorant Christian fundamentalists believing that it has some relation to the end of the world. In reality 6-6-6 is not even an accurate transcription of Revelation 13:17-18, because the oldest sources render it as 616 and nobody thought that June 1st, 2006 was a particularly big deal either.
Thus, while people are trying feverishly to imbue 12-12-12 with special significance, I want to go on record as saying that, in all likelihood, nothing remarkable will happen then, and, if something coincidentally does happen of importance then people will twist all kinds of facts and invent previously unknown quatrains of Nostradumbass, or some other false prophet, in an attempt claim that they knew it all along. Naturally, they only "knew it all along" after the even occurred, which is worthless, as far a prophecies go.