The indie music scene was once just sweaty twentysomethings shouting in converted old factories in Williamsburg — now it’s a bunch of dads, recording kids’ music in their brownstones’ home studios. That said, sometimes this Brooklyn dad music is wonderful. Take “We Like the Zoo (’Cause We’re Animals Too)â€Â from the Walkmen’s bass and organ player Walter Martin and the National’s lead singer Matt Berninger, which is just stupid delightful. It’s off Martin’s star-studded album of kids’ music, We’re All Young Together, which is scheduled to come out May 13. Three cheers to getting older.