Manchasm by the band Future of the Left is about former Senator Mark Foley and his troubles and then morphs into a song about the Singer’s cat Colin.
In Pink Thing by XTC, I always assumed Andy Partridge was singing about his penis.
I have heard that it is either about his penis or his newborn child. But “My Best Friend” by Jellyfish is definitely an Ode to Wang.
Well, it’s a double entendre song that is “really” about a baby.
ETA: ninjaed!
Teargas Jazz by Freak Kitchen is about how the band was advised to keep a low profile in Dehli after the Danish cartoons came out depicting Muhammed, infuriating the local Muslims.
I’m pretty sure “Detachable Penis” by King Missle is about a penis that’s detachable.
I guess that “Pontoon” from Little Big Town can be added to the list and it scored them their first CMA and Grammy award wins, not to mention their first #1 radio release. 
God bless you and them always!!!
Holly
That would be all of Australia, then. 
Until the End of the World, by U2–Jesus and Judas meet up today and have a chat about the last time they saw each other.
Salome, by U2–Herod tries to get out of his deal to bring her John the Baptist’s head on a platter.
I’ll say:
And you, to whom adversity has dealt the final blow
With smiling bastards lying to you everywhere you go
Turn to, and put out all your strength of arm and heart and brain
And like the Mary Ellen Carter, rise again.
He also has an unusual/fun one with The Woodbridge Dog Disaster where the trashman misunderstands the snooty middle class woman and kicks her dog in the balls:
*
And its eyes misted over with pain, boys
And its eyes misted over with pain.*
Any children of the 80s who remember the Dr. Demento radio show?
Dead Puppies are about having the lamest type of pet there is … a dead puppy.
Kinko the Kid Lovin’ Clow is about…guess what.
That’s what I was going to say.
Case in point: Stick It Out and Cy Borg from Joe’s Garage, about a guy joining the First Church of Appliantology and falling in love with and having sex with some sort of bizarre household appliance.
“Magic Bus” by The Who: a guy tries to buy the bus in which he regularly goes to visit his girlfriend, in the implausible belief that this will work out cheaper than having to pay the fare.
Mark Knopfler seems to enjoy writing songs about history and pop culture.
“Sailing to Philadelphia” is about Mason & Dixon, the guys who drew the Mason-Dixon line
“Boom Like That” is about Ray Kroc and the origin of McDonald’s
“Done With Bonaparte” is about Napolean’s defeat in Russia
“Baloney Again” is about segregation in the 50s, from the POV of a traveling gospel choir
“Song for Sunny Liston” - is about the life of the famous boxer
“Back to Tupelo” - is about Elvis’s movie career
Can I add to that list:
“Telegraph Road” - Inspired by a bus trip taken by Knopfler, the lyrics narrate a tale of changing land development over a span of many decades along Telegraph Road in suburban Detroit.
In XTC Song Stories by XTC and Neville Farmer, Andy says “Harry was called Pink Thing when he was born but I love my dick and I’m not afraid to tell people. So it’s about both.”
Tragically Hip have got to up there in terms of different topics
Wheat Kings is about David Milgard, who was imprisoned for 17 years for a crime he didn’t commit
Locked In The Trunk of a Car is about a serial killer
Gus The Polar Bear from Central Park is about a world leaders unpopularity in the polls
The Lonely End of The Rink is about Hockey
But most Hip songs have some complexity to their lyrics and phrases that are not easy to understand.
And so many others by The Tubes. My first thought: Don’t Touch Me There
And let’s not forget Too Drunk to Fuck, by the Dead Kennedys.