Good Riddles

 
Riddle #371 (medium)

Question: You have found a mutant algae that doubles in size every hour. It takes 18 hours for one algae plant to take up half of a certain lake.

How long would it take for two of these plants to take up half of the same lake?

Fortune (medium)

Question: What does it mean when you're reading a fortune?

Funny Riddle (medium)

Question: Why was the fat man sad?

Pain and Fear (medium)

Question: I am pain, I am fear, I will take what you hold dear, Nations shudder when I'm near, Many die when I'm here. What am I?

Riddle #651 (medium)

Question: I can go up a chimney down but not down a chimney up?

What am I?