I got 'K' from lantisescudo. So, in no particular order (just the ones I could find on iTunes):
"Kathy's Waltz" by Dave Brubeck - one of the more normal time signatures on the album Time Out.
"Kick in the Ass" by Moxy Fruvous - a nice little a capella (plus drums) ditty about the people who deserve a kick in the ass.
"Killer Queen" by Queen - In my opinion a mid-range song from Queen, but still pretty good.
"King Herod's Song" from Jesus Christ Superstar - you have to hear this one to believe it. The idea of Herod singing a ditty like this is amazing.
"King of Comedy" by REM - Not much to say about this one. Some of their typical southern-alternative-rock music.
"King of Pain" by the Police - a classic, with some rather poetic imagery that would probably be considered "goth" by today's standards.
"King of Spain" by Moxy Fruvous - A prince-and-the-pauper style song about an abdicated king who goes on to drive the zamboni for the Leafs.
"King of Suede" by Weird Al - A parody of the above Police song.
"Kings" by Steely Dan - I'm honestly not sure what this song is about, but I like its sound.
"Knockin' On Heaven's Door" by Bob Dylan - Another classic. I've also got covers by Def Leppard (I think? Might be Guns'n'Roses) and D.C. Simpson (of Ozy and Millie fame).