Hogwarts Pensieve

The Pensieve of Albus Dumbledore was used during the 1996-1997 school year to give Harry Potter private lessons. It was also used after the death of Severus Snape by Harry Potter to review the memories Snape had given him.

1996-1997 school year
(see article:Harry Potter and Albus Dumbledore's private lessons)

Albus Dumbledore's Pensieve was used during the 1996-1997 school year. Harry Potter reviewed the memories of Bob Odgen, Hokey,Morfin Gaunt, two of Albus Dumbledore's, and Horace Slughorn.

Battle of Hogwarts
After the death of Severus Snape, memories from Snape's childhood came out out his body and into a flask conjured by Hermione Granger. Harry then proceeded to Dumbledore's office to watch the memories Snape had given him.