Actually 5 times. In 1996 Ajax played against Juventus in the Champion League final. Juventus won, but afterwards became known that the players of Juventus used dope. The victory was for Ajax, but the board of Ajax wouldn't receive the price.
Cristiano Ronaldo has won the Champions League once after his United team beat Chelsea in Moscow in his first final. His second Champions League final with United ended in defeat to the hands of Barcelona.
Champions League: once - 2003 (Milan vs Juventus) at Old Trafford. European Cup (pre-1993): five times - 1963 (Milan vs Benfica); 1968 (Man Utd vs Benfica); 1971 (Ajax vs Panathinaikos); 1978 (Liverpool vs Bruges); 1992 (Barcelona vs Sampdoria), all at Wembley.