A planctus ("plaint") is a lament or dirge, a song or poem expressing grief or mourning.
 It became a popular literary form in the Middle Ages, when they were written in Latin and in the vernacular (i.e., the "planh" of the troubadours).
 The most common "planctus" is to mourn the death of a famous person, but a number of other varieties have been identified by Peter Dronke.
 The earliest known example, the "Planctus de obitu Karoli", was composed around 814, on the death of Charlemagne.
All We Are Saying... is a full-length album by American guitarist and composer Bill Frisell of John Lennon classics done in Frisell's definitive style.
 The album features violinist Jenny Scheinman, pedal steel and acoustic guitarist Greg Leisz, bassist Tony Scherr, and drummer Kenny Wollesen.
 The title comes from the first line of the chorus to "Give Peace a Chance".
"Give Peace a Chance" is an anti-war song written by John Lennon (credited to Lennon–McCartney), and performed with Yoko Ono in Montreal, Quebec, Canada.
 Released as a single in 1969 by the Plastic Ono Band on Apple Records (catalogue Apple 13 in the United Kingdom, Apple 1809 in the United States), it is the first solo single issued by Lennon, released when he was still a member of the Beatles, and became an anthem of the American anti-war movement during the 1970s.
 It peaked at number 14 on the "Billboard" Hot 100 and number 2 on the British singles chart.
Botticelli is a guessing game which requires the players to have a good knowledge of biographical details of famous people.
 The game has several variants, but the common theme is that one person or team thinks of a famous person, reveals their initial letter, and then answers yes/no questions to allow other players to guess the identity.
"Give Peace a Chance" is the seventh episode of the sixth season of the American television medical drama "Grey's Anatomy", and the show's 109th episode overall.
 Written by Peter Nowalk and directed by Chandra Wilson, the episode was originally broadcast on the American Broadcasting Company (ABC) in the United States on October 29, 2009.
 "Grey's Anatomy" centers on a group of young doctors in training.
 In this episode, Dr. Derek Shepherd (Patrick Dempsey) performs an operation on a hospital technician's "inoperable" tumor, despite the objections of the chief of surgery, Dr. Richard Webber (James Pickens, Jr.).
Erotomania is a type of delusional disorder where the affected person believes that another person is in love with him or her.
 This belief is usually applied to someone with higher status or a famous person, but can also be applied to a complete stranger.
 Erotomanic delusions often occur in patients with schizophrenia and other psychotic disorders, but can also occur during a manic episode in the context of bipolar I disorder.
 During an erotomanic delusion, the patient believes that a secret admirer is declaring his or her affection for the patient, often by special glances, signals, telepathy, or messages through the media.
 Usually the patient then returns the perceived affection by means of letters, phone calls, gifts, and visits to the unwitting recipient.
 Even though these advances are unexpected and often unwanted, any denial of affection by the object of this delusional love is dismissed by the patient as a ploy to conceal the forbidden love from the rest of the world.
Open Your Box is a remix album by Yoko Ono which was released on April 24, 2007.
 It is a compilation of her successful series of remix singles released since 2001 with the addition of several new mixes.
 Collaborators include Basement Jaxx, Felix Da Housecat and the Pet Shop Boys.
 "You're the One" was released as a single and reached #2 on the "Billboard" Hot Dance Club Play chart in the United States.
 Yoko Ono achieved a number one on the Hot Dance Club Play chart in August 2008 with "Give Peace a Chance".
Here Comes John Allan Cameron is the debut album from Canadian singer/songwriter John Allan Cameron.
 It was recorded at the RCA recording studios in Montreal, Quebec, using the same studio John Lennon used to record Give Peace A Chance.
 The album is notable as being the first professional multi-track recording by a Cape Breton artist.
 The album helped launch Cameron's career abroad, leading to performances at the Newport Folk Festival and Mariposa Folk Festival.
John Lennon Anthology is a four-CD box set of home demos, alternative studio outtakes and other unreleased material recorded by John Lennon over the course of his solo career from "Give Peace a Chance" in 1969 up until the 1980 sessions for "Double Fantasy" and "Milk and Honey".
Da pacem Domine (Give peace, Lord) is the incipit of two different Latin texts, a hymn and an introit.
 Both have been the base for compositions to be used in church liturgy, beginning with chant.
 Paraphrased versions of the hymn were created by Martin Luther in German in 1529, Verleih uns Frieden, also frequently set by composers.
 In English, the hymn entered the "Book of Common Prayer", Give peace in our time, O Lord.

Question: What famous person does All We Are Saying and Give Peace a Chance have in common?
Answer: John Lennon