A Major Numismatic Event In Your Lifetime?

1969. I had been "collecting" coins for a couple of years, that was the year they changed the master dies. I was looking through some new rolls and came across one that didn't have IN GOD on it. I found a few in the rolls with some letters missing. At 14 I thought I had discovered the next 55 doubled die. The older members of my coin club straightened me out at the next meeting. That started me out on the errors and varieties path, which I was on and off till about 2010 when I went full time. I still have that "atheist cent' along with the other greasers.

My moment was emptying my parents old piggy bank long, long ago. It was about the size of a soccer ball, and about 3/4 full of coins--from quarters to cents. Mercury dimes, wheat cents and more wheat cents, Buffalo nickels aplenty, a number of Standing Liberty quarters. Newer material was represented, but not in great numbers. This was back in the days of Steve Canyon and Sea Hunt...

The switch from national currencies in Europe to the Euro?
If I correctly remember, I wasn't thrilled. I thought the Euro looked fake (I still think it closer to monopoly money than any other currency on the planet). But then again, it is quite handy when traveling. No more exchanging "worthless" Belgian francs to Guldens when returning from a wild night in Antwerp!

I can't say any specific moment would classify as a major event. There have been many small events though.

I guess you can say when I came to the U.S. and a neighbor gave me some old U.S. coins (IHC, Bison nickels, Mercury dimes, Ike's) got me into U.S. coins. But I have lots of fun memories like finishing the 1940 to 1974 Lincoln set or going to the Whitman coin show or getting my first large note.

Not modern US coins, but since this is about a numismatic lifetime experience, perhaps this is worth posting here, anyway.

In 1971, I was living and working in Manchester, UK for two years.
At that time, I already had a small but growing collection of Roman coins, which included an aureus of Claudius, a solidus of Constantius 11, and a sestertius of Nero, back in Australia.

I wrote to the British Museum Coins and Medals Department, asking to review some of the Roman Collection.
They wrote back to me, with an appointment about 6 weeks into the future, to view that part of the collection.

I duly arrived in London on time, with my letter of appointment, and was ushered into the secure viewing area, used by research students.
I saw tray after tray of Roman aurei, of the two Emperors I was then interested in, those of Augustus and Claudius.

Even though it was a long time ago, it still feels like yesterday, due to my strong and ongoing interest in ancient coins.

The British Museum also a lot of highly historic coins relating to early Australian coinage history.
Sitting in the palm of my hand was Port Philip Gold Pattern Two Ounce (£8), of 1853, of which only two exist, - that example, and the other in the State Museum of South Australia. The British Museum example is illustrated in 'Rennicks Australian Coin and Banknote Values'.

I can relate. Back then coins were for buying comic books, gum and candy.

I was too poor to save silver coins from circulation.