Lots of fun "K" songs. Karma Chameleon -- gotta love Boy George. Killing Me Softly, either Roberta Flack or Lauryn Hill's version (okay, that doesn't fall under fun). Keep On Loving You by REO Speedwagon. Key Largo by Bertie Higgins (whoever he is); but I remember loving the song. Kokomo by the Beach Boys. Kookaburra.
In honor of my beloved husband, I think I'll go with King of the Road. This is one of those songs that I didn't realize was a real song; I thought my husband had made it up.