Prisoner of Azkaban:

• Holding hands during Care of Magical Creatures
• At the Shrieking Shack

Half-Blood Prince:

• Ron in the Hospital Wing
• Ron makes it snow in the Great Hall

Deathly Hallows Part One:

• Arriving at the Burrow after the attack on the Seven Potters
• Bill and Fleur's wedding is attacked
• Hermione is rescued at Malfoy Manor
• Dobby dies

Deathly Hallows Part Two:

• THE KISS
• Ron opens the Chamber of Secrets
• Holding hands on the Grand Staircase
• Nagini attacks
• Holding hands after the Battle of Hogwarts