My personal winner is in cricket, England winning the Ashes away in Australia 2010-11, led by Ali Cook's extraordinary quantity of runs
Aside from that:
Rugby:
Japan bearing South Africa, it was just such a wonderful Boys Own underdog moment that brought the whole rugby world (aviary from Saffas) together.
England smashing NZ at Twickenham, doubly special because I WAS THERE, MAN!!!
Fiji winning the 7s Olympic gold, highly emotionally.
Non-rugby:
2012 Olympics were excellent all round, especially super Saturday.
Danny Willet's Masters win stands out for sheer unexpected value, combined with the drama of Spieth's spectacular collapse.
Mickelson Vs Stenson's epic battle was something else.
Sergio's first major worth mentioning too.
Don't follow football at all but Leicester winning the Prem was incredible, even I noticed.
Murray's first major, stayed up to watch an epic final in the US open