For the first one, the guy is in college, he should know Achilles, if not for the heel, then the mythological character. Probably not as funny as the next 2.
The second one is funny as there is no way it could have been car, as the letter "R" had already been used. The way the show works is they give you a clue, like CHARACTER, BEFORE & AFTER and THING for a puzzle. The contestants then spin the wheel for money. When the wheel stops, you pick a letter. If that letter is in the puzzle, it gets displayed and you win that amount of money for each time that letter is in the puzzle. If the letter isn't in the puzzle, you lose your turn. So with the second one, The letter "R" was already in the word WORLD, so there is no way it could have been CAR.
I find the last one the most hysterical and the one I laughed the hardest at. DICESPIN!?!?!?!? What the fuck is DICESPIN? The look on the girl from Texas A&M was priceless. She was actually laughing at him. MORON!!!