Classic Riddles
Riddle: What can burn the eyes, sting the mouth, yet be consumed?
Answer: Salt.
Riddle: I am a word of three syllables, each of which is a word; my first is an article in common use; my second, an animal of uncommon intelligence; my third, though not an animal, is used in carrying burdens. My whole is a useful art. What am I?
Answer: Pen-man-ship.
Riddle: I am a word of five letters. Take away my first and I am the name of what adorns the estate of many of the nobility of England. Take away my first and second, and I am the name of a place where all the world was once congregated. Take away my last, and I am the name of a beautiful mineral. Take away my two last, and I am the name of a fashionable place of resort. I am small in stature but capable of doing a great deal of mischief, as I once did in London in the year 1666. What word am I?
Answer: Spark.
Riddle: A hiker comes to a fork in the road and doesn't know which way to go to reach his destination. There are two men at the fork, one of whom always tells the truth while the other always lies. The hiker doesn't know which is which, though. He may ask one of the men only one question to find his way. Which man does he ask, and what is the question?
Answer: Either man should be asked the following question: "If I were to ask you if this is the way I should go, would you say yes?" While asking the question, the hiker should be pointing at either of the directions going from the fork.
Riddle: I build up castles. I tear down mountains. I make some men blind, I help others to see. What am I?
Answer: Sand.
Riddle: It keeps something that cannot be kept, And wakes you when you have slept. It may go slow or stop at times, But even then it chimes.  What is it?
Answer: An alarm clock. “It keeps something that cannot be kept”: Time can’t be held; a clock only measures it as it slips by. “And wakes you when you have slept”: The alarm rings to wake you. “It may go slow or stop at times”: Clocks can run slow or stop (dead battery, mechanical hiccup). “But even then it chimes”: Many clocks still chime or ring on the hour/alarm, even if their timekeeping isn’t perfect. 
Riddle: Why would Snow White be a good judge?
Answer: Because she's the fairest in the land.
Riddle: How high would you have to count before you would use the letter A in the English language spelling of a whole number?
Answer: One thousand.
Riddle: This thing all things devours: Birds, beasts, trees, flowers; Gnaws iron, bites steel; Grinds hard stones to meal; Slays king, ruins town, And beats high mountain down. What am I?
Answer: Time!
Riddle: Formed long ago, yet made today, Employed while others sleep. What none would freely give away. Nor any wish to keep. What is it?
Answer: A bed.
Riddle: General Gasslefield, accused of high treason, is sentenced to death by court-martial. He is allowed to make a final statement, after which he will be shot if the statement is false or will be hung if the statement is true. Gasslefield makes his final statement and is released. The Question: What could he have said?
Answer: General Gasslefield said: "I will be shot." If this statement was true, he would have been hung and thus not be shot. But then his statement would be false, which implies that he should be shot, making the statement true again, etc... In other words: the verdict of the court-martial could not be executed and the general was released.
Riddle: What gets bigger the more you take away?
Answer: A hole.
Riddle: My first is a part of the day, My last a conductor of light, My whole to take measure of time, Is useful by day and by night. What am I?
Answer: An Hour-glass.
Riddle: A dagger thrust at my own heart, Dictates the way I'm swayed. Left I stand, and right I yield, To the twisting of the blade. What am I?
Answer: A Lock.
Riddle: Why is green grass like a mouse?
Answer: Green grass is like a mouse, because the cattle eat it (cat’ll eat it).
Riddle: A leathery snake, With a stinging bite, I'll stay coiled up, Unless I must fight. What am I?
Answer: The answer is “a whip.” Multiple riddle collections list the solution as a whip for this exact clue set.  Leathery snake: A whip is often made of leather and long, flexible, and sinuous—like a snake. Stinging bite: The crack of a whip delivers a sharp, stinging strike. Coiled up: Whips are commonly stored coiled. Unless I must fight: It stays coiled until it’s needed, then uncoils for use (historically in control, sport, or combat).
Riddle: What creature has one voice, but has four feet in the morning, two feet in the afternoon, and three feet in the evening?
Answer: Man crawls on all fours as a baby, walks on two as an adult, and needs a walking cane when old.  The Sphinx posed this riddle to Oedipus who solved the riddle correctly.
Riddle: In camps about the centre I appear; In smiling meadows seen throughout the year; The silent angler views me in the streams, And all must trace me in their morning dreams, First in the mob conspicuous I stand, Proud of the lead, and ever in command. What am I?
Answer: The letter M.
Riddle: Name a five letter word which has three consonants all the same and two different vowels. Every now and then you see this while running a Windows 95/98 on your PC. What is it?
Answer: Error!
Riddle: As I was walking across the London Bridge, I met a man who tipped his hat and drew his cane, and in this riddle, I said his name. What is it?
Answer: And drew = ANDREW.