There are just so many from various sports, but for now:
The epic battle of Alkmaar. Which saw us through to the 2004/2005 UEFA Cup final after a thrilling match and a decisive goal from our then right-back defender in the very last minute of compensation time of the game. Everytime I see Ron Vlaar playing nowadays I remember that he made his European debut against us in this match.
Here's the deciding moment that still lasts in the collective memory of all Sporting fans and Portuguese people in general:
The title match against the now extinct Salgueiros that would make us win the championship 18 years after the last one. Good memories re-watching this, Schmeichel's emotional playing style, the now deceased Miki Fehér and what I still consider to be the player with best freek kick accuracy I've ever seen in action, Brazilian defender André Cruz, netting a couple on this match. Also much simpler football from simpler better days, before it all became the big business it is nowadays. Well worth the watch:
Now for favorite moments in terms of entertainment
Vítor Baía being lobbed from the midfield against Marítimo was a local joke for many years. And yes, that's a younger looking Fernando Santos there too
Despite this forgettable match he had led Porto to their 5th consecutive title the year before.
There's nothing better than watching your most fierce and eternal rival getting completely beaten and trashed, right? Also in the collective memory of all Portuguese is the unforgettable match that saw Benfica losing to Celta de Vigo 7-0
If a Benfica supporter needs to be silenced nowadays, bringing this subject up will prove to still be very effective in either that or at least making them run out of arguments. I only feel bad now for the late
Robert Enke because I read from his posthumous biography that he took this defeat pretty harshly on himself, though you can actually notice there's nearly nothing he could have done to stop all those goals that night, Benfica's defense (and team) at the time were just that terrible. Come to think of it, the Brazilian national team should have watched tapes of this match following their defeat to Germany last week
And for some strange reason I can't find the memorable penalty shootout of Euro 2004 against England
Only from 2006. But that's something the world still remembers very well, right?