When I was a little kid, my granny used to say “If pigs had wings, they’d fly to the moon.” If I had heard this bacon story, I’d have believed it. Obviously the pigs with wings had flown to the moon, and bam! they were turned into bacon. Sounds reasonable to me.
My parents’ friend Uncle Charlie did the same thing to his kids and us with his garage door opener.
ATM’s are manned by chimpanzees. That’s why they go “Eh, eh, eh, eh” when they’re about to dispense the money. They used to have people at teller windows, but then they realized you could save a lot of money with chimps. You just have to feed 'em a few bannanas a day.
Also, see “Calvin and Hobbes” for a bunch of good ones from Calvin’s dad.
In one previous home reorg, I put the living room’s center table in storage. My boy asked where it went. I told him that his younger sister had eaten it. Every day for the next 2 weeks he would wake up, run to the living room and say “She ate the table”. He eventually let it go and we forgot about it. Months later, we put that center table in their play room, for them to play. As soon as he saw it, he turned to his sister and put a hand on her tummy and asked her “Are you ok?”, looking all concerned as if she had just puked it.
This reminds me of the Far Side cartoon with the mom telling the kid to be good and fall asleep or else the Horrible Monster Outside will get him. This monster was a balloon with a face drawn on that they held by a string from the first floor 
“Stop picking your nose unless you want your head to cave in!”
I’ve been working as a substitute teacher lately. One afternoon, as I was walking the older kids down the hall to the buses, a kindergartener grinned at me and asked, “Are you a leprechaun?” Without breaking my stride, I said, “Yeah.” Just before I walked past him, I saw his eyes grow really big and his mouth drop open. When I turned around about thirty seconds later, all the kindergarteners were pointing at me, staring and whispering excitedly to one another.
I worked in their class about a week later, and I used my leprechaun magic to my advantage, healing minor wounds and performing sleight-of-hand tricks to amaze them. One savvy girl said, “He might not be a leprechaun. Maybe he’s just Irish,” which cracked me up. Eventually some other kids worked out that if I was a leprechaun I’d be a lot smaller, and the jig, so to speak, was up.
Daniel
When my dad used to tell tales about his childhood long before, he’d always begin wistfully, “When I was a little girl…” It took my sisters and me years to catch on that he was kidding. When I tried that with my own young sons, they immediately called me on it.
Little bastards.
Don’t cross your eyes or they’ll stick like that.
Don’t run down the stairs or it will make the whole house fall down.
When I was young, my mother told me that if we chewed our nails, the chewed nails in our stomachs would turn into worms & eat us from the inside out. My sister stopped chewing her nails; I still do. I didn’t realize that she meant we had parasites under our nails that could become ringworms (or other yucky things in the southern US).
My middle son is (was) a nose picker, and had been since he was old enough to semi control his hand. While surfing the web one night I stumble across a picture of a fairly pretty lady showing before and after pictures. The after one was the result of her cocaine habit destroying the cartilege in her nose. I showed him the pictures and said she picked her nose too much. Cured that bad habit that night. I’m soo going to hell for that one.
My youngest 2 boys think girls don’t fart. They correct big brother and dad all the time.
I told my kid sister the night before her 7th birthday that she would wake up with new skin…molted like a snake.
There’s a grain of truth in this, since skin cells replace themselves every seven years.
She was NOT pleased.
That reminds me of a story…
A mother is trying to convince her young daughter to stop biting her nails. She tells her that if she bites her nails they will form into a huge ball in her stomach. A few days later when they are at the park the little girl sees a lady who is very pregnant. She marches up to her and in a very stern voice says “I know what you’ve been doing!”
My oldest niece trusted me, God knows why. She once asked why pigs had such cute curly little tails and I told her that pigs were born with long, beautiful tails that had to be cut off short. Naturally she wanted to know why and I told her that if their tails were left long, they would accumulate balls of mud at the end; those balls would get progressively heavier and heavier until the weight of the mud would stretch the pigs skin. When the skin was stretched tight, the pig wouldn’t be able to close its eyes and therefore couldn’t sleep. If it couldn’t sleep, it wouldn’t gain weight and the farmer would be unable to sell it.* She believed that story, especially after her father confirmed it; when she learned the truth, she refused to speak to me for quite a while.
*I THINK I actually read this lie somewhere but I’m not sure. If I didn’t, I’ll gladly claim it but I’m just not positive.
If you go to Baskin Robbins (the ice cream place for the unfamiliar) you can get a sample of ice cream which is given to you on a tiny pink plastic spoon. My uncle had me convinced that if I chewed on those spoons long enough it would turn into bubble gum. I would be so mad when he would be chewing his bubble gum (obviously a devious switcheroo) and I would be chewing on a splintered plastic spoon. I will proudly pass this on to my own children and nieces and nephews.
Everyone knows spaghetti (the pasta, not the whole dish) grows in fields and is harvested and dried.
StG
At my parents’ house, the grandchildren aren’t allowed to open the cellar door because it’s got a really steep staircase. This naturally makes the cellar a place of mystery and wonder. I witnessed one of my young nieces quizzing my father about what the cellar was like.
“Are there spiders down there?”
“Yes.”
“Are there monkeys down there?”
“Of course.”
“What do the monkeys eat?”
“They eat the spiders.”
There were no more questions after this. Apparently she was satisfied knowing that the cellar had a balanced ecology.
Well, duh! http://youtube.com/watch?v=Mb6XLunYtIE
My uncle once told my older sister that you could fart in a bottle, cap it quickly, and sell it as natural gas. It filtered down to me, and we imagined factories in Texas full of workers feverishly chugging 7-Up and flatulating into Rube Goldberg machines with propane bottles coming off the assembly line. Our parents had a good laugh until the garage was overwhelmed with 2-liter bottles. Dad put an end to our sure-fire college fund scheme.
I once convinced my sister that curly fries were actually fried pigs tails. Seemed plausible to her naive mind given the proliferation of fried pork rinds. To this day, she avoids the fast food joint with the Oven Mitt.
I told my friend’s 4 year old that you can’t buy adult sized clothes at the store. You have to water your clothes every night so they grow when you do.
He asked me once why rocks were so heavy, and I told him they had to be to hold down the ground. Otherwise the ground would float away and we would only have sky.
When a (different) friend was little her dad would magically make it stop raining for a few seconds when they were out driving. It wasn’t until she was an adult that she realized they would be passing under a bridge when the rain stopped.