Open Up Your Heart (And Let the Sunshine In)
The biggest hit version in the United States was a recording by the Cowboy Church Sunday School (peaking at #8 on the Billboard charts); in the United Kingdom, by Joan Regan and her son Rusty. Another US recording was made by the McGuire Sisters.
When the Cowboy Church Sunday School version is played at normal speed, 45 rpm, the vocal sounds unnaturally high. When played at 33⅓ rpm the vocal sounds more natural. In fact the song was recorded at that speed by Stuart Hamblen's wife and adult daughters, so that when played at 45rpm it sounds as if it is being sung by children.
The version sung by The Cowboy Church Sunday School was featured twice in the John Waters film A Dirty Shame. The song was first used as an angelic juxtaposition to the intolerant concept of NIMBY. It was later used satirically in a scene depicting the religious aspects of 12-step programs.
The melody of the chorus section is identical for its first two measures to the published version of Aloha Oe by Princess Lili`uokalani (1878), and "There's Music In the Air" by George F. Root (1854), and all three share the same chord progression IV-I-V-I.
- The most famous recording of this song was created for baby-boomers and featured Pebbles and Bamm-Bamm on The Flintstones "No Biz Like Show Biz" episode (which originally aired September 17, 1965). The clip of them performing this song was sometimes played during the closing credits in the show's final season (1965–1966), this episode being the opener of that season. Although Pebbles and Bamm Bamm went on to form a rock band as teenagers in the 1970s, they never approached the classic heights of their early childhood tune. The Flintstones version of the song was not stripped of its religious lyrics for inclusion in the show, and only the word "kids" was substituted. Original vocals were provided by Rebecca Page (as Pebbles) and her mother Ricky Page (as Bamm Bamm), who later became "The Bermudas" and then "The Majorettes". They were managed by George Motola, who was Ricky's husband.
- Anne Murray included the song (in a medley with "You Are My Sunshine") on her 1977 album There's a Hippo in My Tub.
- Husband and wife country duo The Wrights included the song on their album In the Summertime, a CD composed entirely of all acoustic covers of country standards.
- Frente! recorded a cover of the song for inclusion on the 1995 tribute album Saturday Morning: Cartoons’ Greatest Hits, produced by Ralph Sall for MCA Records.
- CD liner notes: Saturday Mornings: Cartoons’ Greatest Hits, 1995 MCA Records