Are you a liar?
A party has 100 people who are either liars or truth tellers.
Liars always lie, and truth tellers always speak the truth.
After the party is over, you ask each person, "How many truth tellers did you shake hands with?"
Each person gave a different answer, ranging from 0 to 99 (the answers were 0, 1, 2, ... , 98, 99).
How many liars were at the party?