Crystal Palace have never won the FA Cup; Manchester United haven't won it in surprisingly long time. Twelve years, to be exact, since 2004. They faced another London team that year in the final, Millwall, who weren't even in the Premier League, but were managed by none other than Dennis Wise (a player-manager, actually, in the grand old tradition, playing in his final ever match; Ray Wilkins assistant manager, too). Millwall had plenty of injuries and were well and truly outmatched, but did start a young Tim Cahill (his last game ever for Millwall), just before he hit the big time.
Millwall's left back was an Irishman named Robbie Ryan, who was also playing his last game for the club and who had the unenviable task of marking Cristiano Ronaldo. I highly recommend listening to his interview on the Second Captains Football Podcast with former teammate Richie Sadler alongside the podcast's regular host. Starts around the 39-minute mark.
FOOTBALL (all times BST):
15.00: Scottish FA Cup, final: Rangers vs. Hibernian
17.30: FA Cup, final: Crystal Palace vs. Manchester United
18.45: DFB-Pokal, final: Bayern Munich vs. BVB
19.45: Coppa Italia, final: AC Milan vs. Juventus
20.00: Coupe de France, final: Olympique Marseille vs. PSG
20.00: MLS, 2nd(E) vs. 5th(E): NYCFC vs. New York Red Bulls
22.00: MLS, 4th(E) vs. 9th(E): Toronto FC vs. Columbus Crew SC
00.30 (next day): MLS, 8th(E) vs. 3rd(E): Orlando City vs. Montreal Impact
02.30 (next day): Liga MX, s/final, 2nd leg: Monterrey vs. Club América (0-1 agg.)
03.00 (next day): MLS, 8th(W) vs. 1st(W): Seattle Sounders vs. Colorado Rapids