Riddle: How can you cut a cheese round into 8 pieces with only three cuts?
Answer: First you cut the cylinder lengthwise. With the two pieces stacked end to end, you cut the cheese into quarters with two cuts.  The result is three cuts and 8 pieces of cheese. See the image below for three cuts needed to divide a cheese round into eight pieces.
Riddle: I climbed a cherry tree, where I found cherries. I didn't pick cherries, nor did I leave cherries. How did I achieve this?
Answer: The cherry tree held two cherries. I pick a cherry and left a cherry.
Riddle: What sings and has ten feet?
Answer: A quintet.
Riddle: Why do black sheep eat less than white sheep?
Answer: Because there are less black sheep in the world than white.
Riddle: Where do sheep get a hair cut?
Answer: The baa-baa shop!
Riddle: What three common songs have the same melody?
Answer: Baa Baa Black Sheep, Twinkle twinkle little star, and the Alphabet song! All kid songs
Riddle: When do you see sheep in ink?
Answer: When you draw them in pen!
Riddle: My last five letters refer to a raised line on the surface of something; my whole refer to a thin tube containing ink inside a pen. My first three & four letters both refer to vehicles. I am a word of nine letters. What Word am I?
Answer: A Cartridge.
Riddle: What seven letters English word is itself an isogram?
Answer: The word "Isogram".
Riddle: What gets dirtier the more you washes?
Answer: Water.