Here's a batch of Lovecraftian Limericks from alt.horror.cthulhu:

There was a young plebe Miskatonic,
Whose story was really ironic,
     He read an old book,
     And took a good look,
And now he's a high priest of the Cthonic.
         - Jonathan Sivier (j-sivier@staff.uiuc.edu)

There was a young plebe Miskatonic,
Whose story was really ironic,
     He read an old book,
     And took a good look,
Now he's Cthulhu's high colonic.
         - Bill Tigrak [posted by Jonathan Sivier (j-sivier@staff.uiuc.edu)]

There was a young man from Innsmouth.....
Who cheerfully plighted his trowth
     To a series of wives
     And their nuptial dives
Were the scandalous talk of the South!
         - Jonathan Burns (burns@latcs2.lat.oz.au)

There once was a Mi-Go from Mars
Who took people out past the stars
     He'd skillfully drain
     Each one of their brain
And he never would leave any scars.
         - Dennis Maggard (dmaggard@access.digex.net)
 
I knew a young woman whose dreams
would stalk the night streets of Orleans
     leaving trails of ichor
     which confounded the vicar
who vanished 'midst blood-curdling screams
         - Dave D Rahbari (LeStief@world.std.com)

Confused was the young Innsmouth feller
About the youth of the average town dweller
     He wondered a lot
     Where the old folks had got
But now he knows, and he hides in his cellar
         - Arthur Levesque (bs@boog.org)

Yog-Sothoth most surely is great,
The Old Ones upon on him do wait,
     But who would believe
     That every May Eve
Lavinia Whateley's his date?
         - Dennis Maggard (dmaggard@access.digex.net)

There once was a black goat named Shub,
Who suggested men give her a rub,
     Soon she started to growl,
     From the woods came a howl,
And in nine months she spawned her a cub!
         - Darren Sullivan (speedbmp@ix.netcom.com)

There once was a black goat in the forest,
Whose taste in sex partners was the poorest,
     She mounted a stump,
     Shoved a limb up her rump,
And made her huge orifice the sorest.
         - Darren Sullivan (speedbmp@ix.netcom.com)

A German inside his U-boat
Deep in the Atlantic did float,
     When it ran aground
     A temple he found
That glowed in the darkness to gloat.
         - Dennis Maggard (dmaggard@access.digex.net)

Pickman used models exotic
Well-versed in matters necrotic,
     They're burrowing still
     Out under Copp's Hill
And all who know are psychotic.
         - Dennis Maggard (dmaggard@access.digex.net)

There was a young writer from Providence
Who brilliantly coined his own evidence
     Like weird-sounding names
     (which spawned role-playing games)
And dark tomes about alien revenants
         - Az0th (azoth@netcom6.netcom.com)

The Necronomicon??  *You* can't be shown one!
While the libraries *never* will loan one!
     But if it's so rare
     And guarded with care
Why does every nut case seem to own one?
         - Dennis Maggard (dmaggard@access.digex.net)

There once was a fellow named Blake
Of Trapezohedrons he spake;
     But his soul got posessed.
     The moral? "Don't mess
With Azathoth, for goodness sake!"
         - Daniel Snyder (snydder@ocf.Berkeley.EDU)

The ticket said "One way to Yuggoth"
And the pilot was a big purple moth
     They took my brain out of place
     And put it into a case
Then screamed 'Ia Ia' and took off
         -Ben Swinburn (bs@u.washington.edu)
        
Nyarlathotep loves to play gin
So I had him deal me in
     I bet my life
     which ended in strife
When the cards we used ate off my skin
         -Ben Swinburn (bs@u.washington.edu)

The Mi-Go will fly you to space
With tact and discretion and grace;
     They'll make your excuses
     And run little ruses--
And all to make sure you save face...
          - Steven B. Harris

There was a Great Old One, Cthulhu,
Who wanted a trendy new hair-do.
     Strange aeons he spent
     With his tendrils all bent -
That he longed for an afro, well, who knew?

There once was an amorous shoggoth,
Who yearned for a mi-go from Yuggoth,
     But the mi-go, it fled
     With unreasoning dread
And told the poor shoggoth to bug off.

There was young lady from Maine,
Who said "I shall make it quite plain,
     That from Innsmouth I shan't
     Choose a husband who can't
From dating young tadpoles abstain."
          - Andrew Nellis (bs904@freenet.carleton.ca)

People thought old Alhazred a loon.
His life ended terribly soon.
     His quest for dark knowledge
     Went far beyond college.
He was eaten by a demon, at noon.
          - Jim Goldfrank (jimgold@aol.com)

There once was a young guy from Fuggoth
Who fell deep in love with a sluggoth
     He tried to make time,
     But was foiled by the slime
And so told the sluggoth to fuggoth.
          - Jim Goldfrank (jimgold@aol.com)

There once was a dreamer from Yuggoth
Who wrote of such beings as the Nug-Soth;
     But they hated his work --
     'He had too many quirks'!
I wish these damned critics would ____ off!
          - James Ambuehl (jamesambuehl@webtv.net)

Randolph Carter was a writer of fiction
Who thought hanging in cemetaries was bitchin'
     But he stayed out too late
     And that tempted fate
And now it turns out ol' Warren is missin'
          - Kali (darkstoriez@yahoo.com)

Nyarlathotep is my favorite Elder God
For worshipping him people think me odd
     But they'll all be cryin'
     When they are dyin'
And I couldn't think of something clever that rhymes with God
          - Kali (darkstoriez@yahoo.com)