Vaka is the common name for a track and lead single from which band that takes its name from the frontman's sister, Sigurrós Elín?
Vaka (song): "Vaka" (released as "untitled #1 (a.k.a. "Vaka")") is the common name for the untitled first track and lead single from Sigur Rós' 2002 album "( )". Sigur Rós:  The band is named after Jónsi's sister Sigurrós Elín.
Sigur Rós