Usually ‘Thank You’ by Dido from Stan.
Sometimes ‘Another Night’ by The Real McCoy (1994) if I’m thinkng.
“This is the song that doesn’t end” is the only one that comes to mind.
And The Boxer and Yesterday.
Alessan: Slight nitpick, the actual lyric is:
“She’s well acquainted with the touch of the velvet hand like a lizard on a windowpane…”
Personally, the Beatles song I sing when I’m bored is “While My Guitar Gently Weeps.”
But I also sing snippets of “Call Me Al” or any song from the Annie Get Your Gun musical.
“Rollin” by Limp Bizcuit
A badly off key rendition of “Oh Lord won’t you buy me a mercedes benz”. -Boredom is a HORRIBLE thing !
I can get any song in the world stuck in my head to sing, since I have an amazing memory, but I usually have worship music in my head, especially after going to a convention at Niagara Falls with all the 3-5 hour worship services…
becomes bored
Lord I lift your name on high… clapping to a beat
head hits keyboard and all goes silent
I Would Walk 500 Miles
Yeah, I know, that was just a typo, sort of. You know - you start writing “window”, you automatically finish it with “sill”. But I sing it the way you wrote it.
The Cute Song - by animaniacs
or “This is the song that never ends” by Lambchops 
I sing Irish songs when I’m working too. “Danny Boy”, “Whiskey in the Jar”, and “Molly Malone” get sung the most often.
Damn you, Wyldelf, now I have the Lambchops song stuck in my head…this is the song that doesn’t end…it just goes on and on my friend…
I tend to sing the vocal warm up we did in High School…
dona nobis pacem
Dona
Nobis
Pa-cem, pacem
Dona
Nobis,
paaaaaacem…
dooooooooonaaaaaaa
Noooobis Pacem
Dooooona
Nobiiiis
Paaaaacem.
bows
The tune to the circus clown song, don’t know why, I just do. Or random disney songs.
Kitty
“The Ocean” by Led Zeppelin. Being a drummer, I always do the drumbeat with my hands and feet. And I pride myself on figuring out that the song is in 7/4 time signature. ::bows::
Also, “Operator Plays a Little Pingpong” and “Everybody Way-oh” from the Neverhood. God I love that game.
I also just realized today that I sing Asshole by Denis Leary a lot, although usually only the long-ass ranting part about his 1967 Cadillac El Dorado convertible… hot pink… with whale-skin hubcaps, an all-leather cow interior, and big brown baby seal eyes for headlights…
Only when I’m bored with friends (that know the lyrics, too) do I ever sing the whole thing all the way through.
I constantly…CONSTANTLY…have songs stuck in my head if I’m not actively listening to something. My mom calls it having a “noisy brain”…I have a continuous internal radio which plays songs, snatches of songs, bits of conversations, poems, stand-up routines, imagined conversations (you know, when you have both sides of a conversation with someone…a convo you’ll probably never have, but you play out all possible premutations of it in your head)…
If I’m walking anywhere, I try to get stuck on “Solsbury Hill” by Peter Gabriel. Fantastic walking beat, and the time changes keep it interesting. I usually end up with something from marching band stuck in there as well, but I can almost always get it back.
If I have something stuck in my head that I can’t stand, I’ve found that “All Mixed Up” by 311 gets rid of it nicely.
“If I Were a Rich Man” and “Matchmaker” from “Fiddler” get me, as do several songs from “The Pirates of Penzance,” “Bye Bye Birdie,” “The Music Man,” “Les Miserables,” “Anything Goes,” “Evita” (which I must mention is because of the original soundtrack; haven’t seen the Madonna-fied travesty)…
You get the idea. It is both a blessing and a curse. A blessing: my car stereo’s faceplate is gone, so I have to come up with my own aural entertainment. A curse: trying to call asleep and “Everything You Know is Wrong” by Weird al won’t stop spinning in my brain, and it’s 3:30 in the morning and I have to be up in a couple of hours.
Almost forgot: almost any and all songs in Tom Lehrer’s repertoire will lodge themselves in my brain given almost any opportunity.
“Aiii, yiiii, yiii-yii, I am the Frito Bandito…”
I have songs constantly running through my head. Lately, it’s been, “I believe that children are our future…” Since I don’t know all the words, I usually sing the beginnig and “I decided long ago never to walk in anyone’s shadow.” It’s fun to belt it.
Also, “Bust a Move” has been in my head a lot lately, probably because I’ve seen Dude, Where’s My Car? four times in two weeks.
Oh, and “Wind Beneath My Wings.” I sing it to my ten-year-old sister all the time, on my knees. “Did you ever know that you’re my hero?..”
I often sing, “Me and yo dawtah got a special thang goin on. You say it’s puppy love, we say it’s full grown…”