How you get to the Hot Quiz in the Desert?
Well, I simply start at the entrance, where that merchant is.
Head to the right and you will pass by some green pattern.
It's best to go like 10 steps north, because at the end of the pattern is a sign, it says: Boat ahead ---> (to the right).
As soon as you read the sign, the boat should appear on the brown pattern, heading south. Speak to the boat and an event will trigger. Speak to the clown and tell him you want to go to the "Hot Quiz". Enter the house und proceed with the Quiz.

Round 1:
Question#1: Snowy Land ---> Alathar
Question#2: Imperan Hobby ---> Slavery
Question#3: Airship Name ---> Artemis

Reward: Riddel's Ring - Prevents Confusion

After round 1, just proceed the game. The NPC needs time to think of some new questions, so be patient. =)

Round 2:
Question#1: Arena Champion ---> Harkon
Question#2: Jenise's Ruler ---> Belet
Question#3: Elven Land ---> Ferdel

Reward: Quizzer's Cloak - Improves evasion and magic evasion

Proceed further in the game, although I don't know exactly what triggers the new round. Just in case read every book you find.

Round 3:
Question#1: Old Religion ---> Luminosity
Question#2: Water God ---> Crodin
Question#3: Evil Power ---> Armagen

Reward: Quizzer's Glove - Nullifies water and ice damage.

Originally posted by Endeus (Thanks a lot dude!)