Opening bookshelves:
At Hogwarts there are bookshelves you can open 
and get prizes. 
There are 2 in the Great Foyer. 
There is also 1 outside the Gryffindor Common Room.
The nearest bookshelve to the portrait of the Fat 
Lady can open up. 
by unknown

All the non climbable bookcases can be opened. 
There you will find many cards.
Submitted by Tommy