My most memorable Hand On-line Has to be when I was down to around 3 BBs left in a Tournament and still not made the money, I was on the BB and dealt K/10 Heart suited, and an aggressive player raised my BB, and another player called the raise, I decided There really was only one solution, So In for a Penny, I shoved all-in.
The 2 players called and the Flop gave me the Royal Flush, It was a good job I was playing on-line as I burst into laughter and couldn't stop laughing as the other players were fighting over a lost cause, I had the "Nuts" and nothing was going to stop me making the money, I actually made the final table, and took a decent prize.
In a Live game I think the most memorable hand was when I was heads up against a player who shoved all-in with an A/K suited, and I snap called without even looking at my two cards, My reason was that I had a massive chip stack and didn't care if I doubled him up or not, When the dealer turned my cards over, this other player laughed at my miserable 6/2 off and said I was Stupid not looking before I called. The Flop and Turn didn't improve either hand, until the River paired my 2 and I won with a pair.
I just said "If I had looked I would never have called, and folded the winning hand" My Friends that were there Laughed so much, they even took Photos of me holding the 6/2 off as if I had Won the World Series with it, A night I will never forget!