Skullcrusher Mountain by Jonathan Coulton. The bit about the half monkey, half pony monster makes me laugh hard every time I listen to it. Heck, I’m giggling just thinking about it.
“What’s with all the screaming? You like ponies, you like monkeys …” 
As a matter of fact just today I was singing I Need a Nap (sung by Weird Al and Kate Winslet of all people) and (Don’t Give Me That) Broccoli, from Dog Train, a collaboration of Sandra Boynton and various artists. Not only are they hilarious, they’re catchy and fun to sing - enough so that I included them in my kid-friendly-but-not-necessarily-kid-music tape for the car.
Surprised no one mentioned The Lonely Planet / Andy Sandburg / Justine Timberlake SNL videos:
I’m On A Boat
Jizz My Pants
Dick in a Box
Mother Lover
The Team America songs are also pretty good (if you like that cheesy 80s movie soundtrack sound):
Montage
America! (Fuck Yeah!)
It’s just the lyrics are silly.
I don’t know if it qualifies as “pretty good”, but Boris The Spider was always a fan favorite at Who concerts.
ps: add me to the list of people who remember The Royal Guardsmen.
Just thought of We Are The Nowtones by Blotto. This is also the first song that I failed to find on Youtube.
Well I never.
It is indeed possible I have overstated the romantic frisson liable to be generated by this song but, at the same time, it had never occurred to me to connect the multi-bass instrumentation with the title.
While I don’t quite feel like an idiot for this oversight, I’m well on the way there.
A few Tenacious D songs cross the line from amusing novelty tunes to actual good songs:
And a surprisingly sweet tune (with not so sweet lyrics):
Fuck Her Gently
A little obscenity in each, so don’t listen at work, but I mostly avoided the real videos. Jack Black doesn’t have a bad voice when he’s not trying to be a joke, and they’re well-put-together tunes.
We all knew the Snoopy songs when we were kids (I’m 40), I still have the LP somewhere.
Of course, it still gets regular airplay around Christmas here in Canada.
Correction: they call themselves The Lonely Island. Their recent CD Incredibad has some additional awesome tunes on it. “Boombox” is a personal favorite.
I always liked “Telephone Man” by Meri Wilson.
Does “Surfin’ Bird” by the Trashmen count as a novelty song?
The Royal Guardsmen put out four LPs in the '60s: Snoopy Vs. The Red Baron, Return of the Red Baron, Snoopy and His Friends, and Snoopy for President. All of which were released on a pair of CDs in 2001. I happen to have a fifth LP that I’ve never found listed anywhere, Side A is their Snoopy songs, minus the Christmas one, and about a dozen of their covers; side B is The Vince Guaraldi Trio with theme music from the '60s specials.
I’m surprised that I’m the first to post
I’m an Asshole! by Dennis Leary. If you’ve enjoyed any of his comedy, you’ll probably love the song.
I use certain sections of the lyrics probably weekly. Especially in the summer…
“I walk around in the summertime saying “Howabout this heat!””
I’m also a huge fan of the Snoopy songs. I got curious if these guys were still alive and went to the Wikipedia article and was surprised to see that a band still performs under that name (looks like with some of the same people) and not too long ago made Snoopy vs. Osama
Looks like a sample is available on the Royal Guardsmen website
http://www.theroyalguardsmen.com/SvOCD.htm
And he makes ‘Baby Got Back’ almost a pretty song.
Perhaps that’s because this is supposed to be about songs that are actually pretty good.
I dunno, I guess maybe they’re pretty good on some level, but for me, I got my fill of that “how crass can we be” schtick in junior high. I’d rather listen to fingernails on a chalkboard than The Lonely Island. I suppose that’s just me being an old fart.
Another one I’d forgotten about:
I’ve always liked the Irish Rovers - “Wasn’t That a Party” and “The Unicorn Song” 
And not to forget my favorite Weird Al song “One More Minute” (‘I’d rather clean all the bathrooms in Grand Central Station with my tongue then spend one more minute with you…!’ :eek: )
What, no Tom Lehrer?
Shaddap Your Face by Joe Dolce
“Tie Me Kangaroo Down Sport” by Rolf Harris.