Celtic's win over Inter Milan in the 1967 final (the first European Cup win for a British club) was considered not just a CMOA for Celtic, but a victory for football (with Inter Milan's manager even saying that), with Celtic's attacking power overcoming Inter Milan's Catenaccio (a more defensive system) and overturning a 1-0 deficit to win the trophy.
Also a CMOA for Scottish football; all eleven Celtic players and manager Jock Stein were born within 30 miles of Glasgow (in fact, with the exception of Ayrshire native Bobby Lennox, they were all from what would be considered the greater Glasgow area). That same year, Celtic also won the Scottish League, the Scottish League Cup, the Scottish Cup, and the Glasgow Cup, a grand slam unparalleled in British football.note Manchester United came closest in 1999, but were knocked out of the League Cup quarter-final by eventual winners Tottenham Hotspur.
Madjer's goal for Porto against Bayern Munich in the 1987 Cup Final. It was the equalizer that turned the game in Porto's favour (the second goal came just three minutes later, scored by Juary). Porto won 2-1 and got their first Champions Cup. It remains one of the greatest moments in Porto's history and is still fondly remembered even by fans who weren't born then. Pelé is believed to have said of this goal: "It would have been the greatest goal I have ever seen, if he had not looked back at it."
The 1999 final, Manchester United vs. Bayern Munich. Bayern scored first, in the 6th minute, and after the standard 90 minutes had elapsed, it looked like it was all over bar the shouting. United then goes on to score two goals, in injury time, to win the match and the championship - literally at the last possible moment. UEFA president Lennart Johansson had left the stands a few minutes before United equalised, and did not see either goal. When he walked out with the trophy, he said, "It cannot be. The winners are crying and the losers are dancing."
This capped off a historic season for Manchester United which also saw them win the Premier League and FA Cup. This also led to an Epic Fail for Bayern Munich, as they were on course to complete that same feat in Germany and the German season ends after the English, but after they lost to United, they also lost the DFB-Pokal final to Werder Bremen and only ended up winning the Bundesliga.
The 2002 final between Bayer Leverkusen and Real Madrid. Raúl scored an impressive goal at minute 8 by taking advantage of a lapse in concentration by Bayer's back. Lúcio managed to tie five minutes later. First half is about to finish, when Roberto Carlos kicks the ball high into the sky. Zidane sees the ball, readies himself... and manages to volley the ball on the corner of the goal with an impressive kick. See it here.
The 2005 final, AC Milan vs. Liverpool. AC Milan had won the tournament two years previously and entered the final overwhelming favourites with a side that featured seven players who had been named in the previous year's FIFA 100; Liverpool, who had no FIFA 100 players on their roster, had not won the tournament since 1984. AC Milan took the lead in the first minute of the match and completely outplayed Liverpool to finish the first half with a 3-0 lead. Eight minutes into the second half, Liverpool managed to score three goals in six minutes (including a rebound from a missed penalty) and held their ground through extra time to force a penalty shootout, in which Liverpool goalkeeper Jerzy Dudek saved two penalties and a third missed the goalmouth to give Liverpool a 3-2 win. The match has since become known by Liverpool fans as "The Miracle of Istanbul".
To add to the awesome factor, the 2005 win was Liverpool's fifth, making them the first English club to be given the trophy permanently.note According to UEFA rules, a club is allowed to keep the trophy permanently (a new one is struck for the following year) if they win either five times total or three years running; the other clubs to have achieved this feat are Real Madrid (1960), Ajax Amsterdam (1973), Bayern Munich (1976), and AC Milan (1994). Moreover, Liverpool had very nearly failed to progress past the group stage in the competition, needing to beat Olympiacos Piraeus of Greece by two clear goals in their final group match and only scoring the deciding goal in the last ten minutes.
The 2009 Chelsea-Barcelona semifinal was an awesome moment for Barcelona. After a 0-0 draw (with a denied penalty for Barcelona) at Camp Nou, where Chelsea did a great job stopping the locals' famous football, they took advantage of the home support and scored first, forcing the Spaniards to draw the match to get to the final on away goals. The referee denied Chelsea a few arguable penalties (and a rather clear one), and instead gave out a straight red card to the Barcelona player Abidal for pretty much being near a Chelsea player who collapsed during a run to the goal, forcing them to spend the last 30 minutes with one player down. Chelsea felt they had the job done and put on some more defenders. In the 92nd minute, Andrés Iniesta scored the equalizer, starting a massive celebration by the Barcelona fans (he pulled off a similar feat during the 2010 World Cup - someone said, "He doesn't score too many goals, but when he does, they go all over the world").
Chelsea would get their revenge three years later. Barcelona needed to win by two goals at Camp Nou after losing 1-0 at Stamford Bridge. Egged on by the home crowd, and with one Chelsea defender (Gary Cahill) injured early on and another (John Terry) sent off, Barcelona raced into a two-goal lead. However, Chelsea's Ramires scored a spectacular goal to pull back and give Chelsea the lead on away goals just before half time, before Leo Messi missed a penalty. Barcelona spent much of the second half trying to break through the Chelsea defence (at 2-1, Chelsea would go through on away goals), before, in stoppage time, Chelsea's misfiring striker Fernando Torres broke free in the Barcelona half and rounded the keeper before putting the ball in the empty net and sending Chelsea through on aggregate.
When Tottenham Hotspur played European Champions Inter away from home in the 2010-11 group stage, they were saved from a humiliating 4-0 loss by Gareth Bale, who scored a hat-trick to make the final score a flattering 4-3. This would have been a CMOA in of itself, if it wasn't for the fact that when Inter came to Tottenham, Bale destroyed them again, although this time, it was a CMOA for the whole team as well, as Tottenham went on to win 3-1.
Chelsea winning the final in 2012. They went 1-0 down with seven minutes left, when with 2 minutes remaining Didier Drogba scored the equaliser and the match went into extra time. Then in extra time, Bayern Munich missed a penalty. Then it went to penalties, and at one miss each Bastian Schweinsteiger struck the post with his spot kick, and up stepped Didier Drogba to win the competition.
Celtic beating Barcelona 2-1 in the 2012-13 Champions League Group Stage, partly because Barcelona had, until this point in the season, been undefeated in all competitions (domestic and European) and were heavily favoured to make short work of Celtic.
The 2013 semi-finals provided an extended moment of awesome for German football. The draw pitted the top two German sides, Bayern Munich and Borussia Dortmund, against the (more favoured) top two Spanish sides, Barcelona and Real Madrid. Bayern Munich proceeded to run rampant in both legs of their semi-final against Barcelona, winning 4-0 in Munich and 3-0 in Barcelona to progress 7-0 on aggregate and hand Barcelona by far their worst aggregate defeat in European competition. Borussia Dortmund, meanwhile, beat Real Madrid 4-1 at home (with all four Dortmund goals scored by Polish striker Robert Lewandowski) and fended off a comeback by Madrid in the second leg to advance 4-3 on aggregate, setting the stage for the first all-German Champions' League final (won 2-1 by Bayern Munich after an 89th minute winner from Arjen Robben, exorcising the ghosts of their final defeats in 2010 and 2012) and capping a decade-long rebuilding process in German football as a whole.