Find the Map Chamber as a Gryffindor

Survive the troll attack on Hogsmeade

Complete the introduction and finish the Sorting Ceremony

Completed "Fair Play"

Won the race

Found a Pulp Magazine

Found a 'Gangsters of the United States' cigarette card

Completed "An Offer You Can't Refuse"

Unlock all trophies

Look in all peepholes and telescopes long enough to hear Edith's commentary

Take a picture of the rabbit outside Odin Finch National Park

Knock all the letters of Gregory's name into the bathtub