This week's challenge is to listen to songs sung by two or more siblings. First, the "sung" part limits us to vocal music. And, since the point of the challenge is to listen beyond the mainstream or already familiar, I bypassed well-known family groups like the Jackson 5 or the Jonas brothers in favor of somewhat lesser known groups; most of the examples on my playlist might be described as "indie" music and are otherwise difficult to describe in terms of genre.
Searching for music performed by siblings is a bit tough-- that's not the kind of information that tends to be included in library descriptions of albums or streaming databases. Instead, we have to rely on press coverage or academic studies that take an interest in that aspect of the performance. It's also tricky because that coverage could describe the performers as siblings, or as brothers, or sisters, depending on the details. Using the operator "OR" in an advanced search gives you the option of including any results that include any of a set of alternative terms.
"Singing Families," in Singing the Glory Down by 
It Still Moves: lost songs, lost highways, and the search for the next American music by 
Mavericks of Sound: conversations with artists who shaped indie and roots music by 