Two of the worst I know would probably be

Whats brown and sticky...a stick.

or

What do you call a man with no arms...shitty bum.

What is better than seeing a woman wrestle?
Seeing her box

What do you get when you drop a piano down a mine shaft?
A flat Minor

A priest, 2 rabbis, 3 blondes and a midget walk in to the bar, bar tender says "what is this? a Joke?"

And with that, I am off like a prom dress.

Knock knock?
Who's there?
My panther.
My panther who?
My panther falling down.

This one comes from the late great Mitch..."Every fight is a food fight if your a CANNIBAL" LOL

KenzS:
lol i randomly thought up this joke and said it to a girl on halo 3.

"If you were trapped under a pile of ice cream, I would eat you out!"

[groan] that's corny. I hope she took it well.

Two men walk into a bar, the third one ducks.

This one came from a movie and I don't get it: What do you get when you cross an owl with a bungee cord? My ass.

How do you kill a blonde? Put a scratch and sniff at the bottom of a pool.

Did you check the up dock?
Up dock, what's up dock?
Nuttin' what's up wit you? nyuk nyuk nyuk! [groan] that's so bad.

What did napoleon say to his men before they got on the boats?

Wait for it....

"Get on the boats."

I apologize for that. If someone wished to kill me i shall be more than willing to travel.

Corjha:
Did ye hear the one about the wall? You'd never get over it.

I dare anyone to make something worse.

I see yours and raise you this

what do you call a lease of false teeth? -- a dental rental

The garbage man sees that this one hose doesn't have a bin out, being nice he knocks on the door.
GM: Mate where's your Bin?
Guy: oh away.
GM: No mate your bin
Guy: On holidays.
GM: No where's your wheely bin.
Guy: Ok, geez I'ze really been in prison.

Not only terrible but actually published in a joke book.

What do you call a Spanish man on a nudist beach?

Senior Willy.

(Diablo joke PLS DON'T HURT ME)
Three Necromancers and a Barbarian walk into Andariels lair.

Wait For It....

And the bartender says "What is this a cheap Dungeon Joke?"

What do you call a fly with no wings?
Jason.

What did the farmer say when he lost his tractor?
"Where's my tractor?"

And another I can't remember...

Whats brown and rhymes with Snoop

- Dr. Dre.

What do you call a monkey filled with helium?
A hot-air baboon.

Here's one that I came up with:

What was the poor kid's name?
Nickle-less.

OK, one time my science teacher was being really corny (more than usual anyway). At one point I told him that he was corny that he'd need to put up a scarecrow. The entire class bust out laughing and everyone agreed that what I just said was cornyer than anything that the teacher ever said.

Drum kit falls down the stairs
Bdum tch!

Why do seaguls fly over the sea?

Because if they flew over the bay, they'd be bayguls. ;D

Why did the chicken cross the road?

To get to the other side.

How do you keep a blonde occupied?

Tell her to sit in the corner in a round room.

Lord_Of_Plum:
Ok.
This joke is absolutely horrible. I mean, horrible. Do not read it unless you have absolutely nothing to do. And it's quite long.

Spoiler: Click to View

[groan] that is such a lame joke.

a seal walks into a bar, the bartender sees it and says, "what'll you have", the seal replies: (get ready for it) anything but canadian club.

two inuit are sitting in their kayak one cold day, they decide to light a fire on it so that they can keep warm, but it does not work and the kayak sinks, proving once and for all that, (get ready again) you cannot have your kayak, and heat it to.

An Irishman, an Englishman, and an Indian chief go fishing together in a rowboat on a lake. Everyone has good luck: 2 or 3 big fish each. They stay out in the middle of the lake until sunset. On the way back to shore, as the sky purples and turns to night, they all sing a song.

chuck norris is the only person who can kill two stones with one bird

What did Goku score on the SAT?

OVER NINE THOUSAAAANNND!!!!!

What cheese isn't yours?

Nach-Yo Cheese

More than likely said but 'a man walks into a bar ouch' is a classic bad joke.

Lukeje:
A neutron walks into a bar. Orders a drink, tries to pay, but the barman stops him. "For you, no charge."

That's good. What did the neutrino say to the Earth?

Just passing through.

CakeDragon:
What do you call a monkey filled with helium?
A hot-air baboon.

You mean a woman?

Lukeje:

notoriouslynx:

What do fish brush their teeth with?
What?
Fish don't have teeth.

http://en.wikipedia.org/wiki/Shark

And on topic:
A neutron walks into a bar. Orders a drink, tries to pay, but the barman stops him. "For you, no charge."

Oh, you sir are awesome.

Brother:A reign of terror is approaching.
Me:Better get an umbrella.

I don't remember what conversation we were having but I do remember that it ended right after I said that.

Okay. So, there's a rich man, in ye olde times, and he's on his way back to his mansion when somebody knocks on the window of his carriage, so he opens the door, and standing there, is a knight. The knight looks at him and says, "I've just fought a terrible dragon, and it's a long way to my kingdom. Please, may I stay and rest at your mansion?" So the rich man says, "Of course!", and he lets the knight into his carriage, and then he drives home. They reach his house, and it's this beautiful, luxurious mansion. They step inside, and the rich man takes the knight to the staircase and says to him: "Go up the stairs, and take the first door on the left," so the knight goes upstairs, and takes the first door on the left, and it opens up into this huge, magnificent bedroom, with an enormous four-poster bed, and an en-suite bathroom, and the knight sits down on the bed, takes his armour off, nurses his burns and falls asleep. Meanwhile, the rich man downstairs is enjoying his pipe, when there's a knock on the door. Now the rich man is thinking "Who could it be at this time of night?" so he goes to the door, and opens it, and there's a knight there, and the knight says "I've just fought in an epic war, and I need somewhere to rest for the night," and the rich man says "O.K., just go up those stairs, and take the second door on the left, and there will be a bed and somewhere to freshen up. So the knight goes upstairs, and he takes the second door on the left, and again, it's a beautiful room. so he freshens up, cleans his wounds, splashes some aftershave on, and falls asleep. Now, downstairs, the rich man is just getting ready to go to bed himself, when he hears a knock on the door! So, he's a little bit annoyed, but he goes and opens it, and there's a beautiful princes-nah, I'm kidding, it's a knight. The knight says that he's just fought a terrible and powerful wizard, blah blah blah, freshen up, yadda yadda yadda. The rich man points him to the second room on the right, the knight goes upstairs, falls onto the bed, you know the rest. A few minutes later, the rich man comes upstairs, goes in the first door on the right, falls asleep.
In the morning, the first knight comes downstairs, and the rich man is there, eating a bowl of cornflakes. He asks the knight what he would like for breakfast, and the knight has a choice between kippers and cornflakes. So the knight thinks, and he decides that he'll have kippers, because it's a good source of protein and all that. So he has his kippers and toast, says goodbye to the rich man, and sets off for his own kingdom. Then, the second knight comes down, and he has cornflakes for breakfast, sets off for his kingdom, the third knight comes down, decides to have kippers. He has his kippers, with toast, and a big wodge of butter, and he eventually sets off.

So, the motto of the story is:

Two out of three knights prefer kippers for breakfast.

Redingold:

So, the motto of the story is:

Two out of three knights prefer kippers for breakfast.

Heh. Heh heh.

That was actually pretty good, in an absurdist way.

What do you call a hooker who works St. Paul & Minneapolis?

ThaBenMan:
A priest, a rabbi, and an atheist are on a plane crossing the Atlantic Ocean. There is engine trouble, and one of the wings catches on fire. The plane starts to go down. Luckily, there are enough parachutes for everyone. Evacuation is orderly.

dude your jokes are really bad, in a good way.

What did Batman say to Robin before They got in the car?

"Robin, get in the car"

BBLIZZARD:

ThaBenMan:
A priest, a rabbi, and an atheist are on a plane crossing the Atlantic Ocean. There is engine trouble, and one of the wings catches on fire. The plane starts to go down. Luckily, there are enough parachutes for everyone. Evacuation is orderly.

dude your jokes are really bad, in a good way.

Thanks. I didn't actually make them up myself; they're from The Areas of My Expertise by John Hodgman. They're from the section "Jokes That Have Never Produced Laughter" (but the whole book is hilarious - there's a section about when hobos staged a government coup in the 50's)