Ahh...the joys of getting chain-mail and believing everything (or anything). Here I debunk many of the facts from a popular email circulating over the internet titled "So you think you know everything" which makes 40 claims of fact.

1. TRUE - A dime has 118 ridges around the edge.
http://www.enchantedlearning.com/math/money/coins/dime/

2. FALSE - A cat has 32 muscles in each ear.
http://www.madsci.org/posts/archives/jun2000/961374691.An.r.html
There are no muscles in the ear exactly, but I guess there are muscles attached to the ear.

3. TRUE - A crocodile cannot stick out its tongue.
http://www.didyouknow.cd/fastfacts/animals.htm
It is stuck to the top of his mouth.

4. FALSE-ISH - A dragonfly has a life span of 24 hours.
http://www.pnl.gov/pals/resource_cards/Dragonflies.stm
Their lifespan varies between 2 hours and 48 hours.

5. FALSE - A goldfish has a memory span of three seconds.
http://www.boston.com/news/globe/health_science/articles/2003/12/02/the_chemical_mind_binds_us_together/
Research has shown goldfish can remember locations from the previous day.

6. TRUE - A "jiffy" is an actual unit of time for 1/100th of a second.
http://www.unc.edu/~rowlett/units/dictJ.html
An alternate meaning is also 33.3564 picoseconds.

7. FALSE-ISH - A shark is the only fish that can blink with both eyes.
http://www.everwonder.com/david/sharks/anatomy/
"Sharks that have no nictitating membranes, like the great white for example, roll their eyes into the back to their heads."  Some sharks don't have eyelids so cannot "blink"...

8. TRUE - A snail can sleep for three years.
http://www.somers.k12.ny.us/SIS/MAIN/sis/research/gr.3research/snails/snailquestions.html
Desert varieties have been known to sleep for this long.

9. TRUE - Al Capone's business card said he was a used furniture dealer.
http://www.wordiq.com/definition/Al_Capone

10. FALSE - All 50 states are listed across the top of the Lincoln Memorial on the back of the $5 bill.
http://www.ustreas.gov/education/faq/currency/portraits.html#q5
Only 48 are on the memorial and only 26 are actually on the front of the building, therefore only 26 on the bill.

11. TRUE - Almonds are a member of the peach family.
http://waynesword.palomar.edu/ecoph17.htm

12. TRUE - An ostrich's eye is bigger than its brain.
http://www.sandiegozoo.org/animalbytes/t-ostrich.html
At a diameter of 2" and a head not much larger there isn't much room for the brain when you do the math!

13. FALSE - Babies are born without kneecaps. They don't appear until the child reaches 2 to 6 years of age.
http://www.fazed.com/phpBB/viewtopic.php?t=3291&view=previous
They just don't calcify (get hard) until they are older.

14. TRUE - Butterflies taste with their feet.
http://www.enchantedlearning.com/subjects/butterfly/allabout/Senses.shtml

15. FALSE - Cats have over one hundred vocal sounds Dogs only have about 10.
The number are too vague and what is a vocal sound?  Does a bark differ from a growl, a purr from a miouw?  Admittedly cats do make more different types of sound.

16. FALSE - "Dreamt" is the only English word that ends in the letters "mt".
http://www.askoxford.com/asktheexperts/faq/aboutwords/dreamt?view=uk
Being pedantic, there is also adreamt and undreamt.

17. FALSE - February 1865 is the only month in recorded history not to have a full moon.
http://www.obliquity.com/astro/february.html
See February 1999.

18. FALSE - In the last 4,000 years, no new animals have been domesticated.
http://en.wikipedia.org/wiki/Domesticated_animal
I guess we didn't start to domesticate insects until we had too! "Many present-day breeds of domestic livestock originated about the middle of the 19th century or later" says:
http://www.anapsid.org/roleofzoos.html

19. FALSE - If the population of China walked past you, in single file, the line would never end because of the rate of reproduction.
At what rate are they walking past? It depends solely on this.

20. FALSE - It's impossible to sneeze with your eyes open
http://content.health.msn.com/content/article/74/89427.htm?pagenumber=2
Extremely difficult but not impossible...

21. TRUE - Leonardo Da Vinci invented the scissors.
http://www.lairweb.org.nz/leonardo/

22. TRUE - Maine is the only state whose name is just one syllable.
Try reading the list here:
http://dir.yahoo.com/News_and_Media/Newspapers/By_Region/U_S__States/

23. TRUE - No word in the English language rhymes with month, orange,
silver, or purple.
http://www.askoxford.com/asktheexperts/faq/aboutwords/orange?view=uk
Although it does depend on your pronunciation. Does 'Thousandth' rhyme with 'month'? Do 'cringe' and 'fringe' rhyme with orange? Does 'Wilbur' rhyme with 'Silver'? You decide.

24. FALSE - On a Canadian two dollar bill, the flag flying over the Parliament building is an American flag.
http://www.indefual.net/canada/myths/

25. FALSE - "Stewardesses" is the longest word typed with only the left hand and "lollipop" with your right.
http://www.fun-with-words.com/word_records.html
Try TETRASTEARATES and PHYLLOPHYLLIN.

26. FALSE - The cruise liner, QE2, moves only six inches for each gallon of diesel that it burns.
http://www.wagoneers.com/DieselBenz/TECH/little-known-facts.html
26 feet actually :-)

27. TRUE - The microwave was invented after a researcher walked by a radar tube and a chocolate bar melted in his pocket.
http://www.ideafinder.com/history/inventions/story068.htm

28. TRUE - The sentence: "The quick brown fox jumps over the lazy dog" uses every letter of the alphabet.
It does just count them!

29. FALSE - The winter of 1932 was so cold that Niagara Falls froze completely solid.
http://www.niagarafallslive.com/Facts_about_Niagara_Falls.htm

30. TRUE - The words 'racecar,' 'kayak' and 'level' are the same whether they are read left to right or right to left (palindromes).
Just try reading them backwards!

31. TRUE - There are 293 ways to make change for a dollar.
http://www.teachnet.com/lesson/math/293changedollar.html

32. FALSE - There are only four words in the English language which end in "dous":
  tremendous, horrendous, stupendous, and hazardous
http://www.onelook.com/?w=*dous&ls=a

33. FALSE - There are two words in the English language that have all five vowels in order:  "abstemious" and "facetious."
http://www.askoxford.com/asktheexperts/faq/aboutwords/fivevowels?view=uk
Try "arsenious" (chemical term meaning like Arsenic).

34. FALSE - There's no Betty Rubble in the Flintstones Chewables Vitamins.
http://www.randomhouse.com/features/straightdope/funfacts2.html

35. TRUE - TYPEWRITER is the longest word that can be made using the letters only on one row of the keyboard.
http://www.fun-with-words.com/word_records.html
But there are also other 10-letter words...

36. FALSE - Winston Churchill was born in a ladies' room during a dance.
http://www.historylearningsite.co.uk/winston_churchill.htm
He was born in Blenheim Palace.  It may have been during a dance but Blenheim Palace then did not have public restrooms.

37. FALSE - Women blink nearly twice as much as men.
Each blink at approximately the same rate on average otherwise studies such as this would be difficult to carry out:
http://digilander.libero.it/linguaggiodelcorpo/interpers17/

38. TRUE - Your stomach has to produce a new layer of mucus every two weeks; otherwise it will digest itself.
http://www.soton.ac.uk/~gk/scifi/stomach.htm

39. TRUE - The average person's left hand does 56% of the typing.
http://www.simonsays.com/ssimkt/typingtutor/html/trivia.html

40. TRUE - There are more chickens than people in the world.
http://www.fao.org/DOCREP/004/AD452E/ad452e30.htm
15 billion and counting...


And there you have it! For more information see the comments from GoogleAnswers.