Misc: The Roman Numeral CMXCIX is what in Arabic?

Questions

Whose work is never done, according to a popular saying?

Why are we playing trivia?

Why did the chicken cross the road?

Widespread disease caused by the infestation of the human body by flukes fluke commonly called blood flukes, of the genus schistosoma?

Wild Bill Hickok was shot in the back by a stranger during a poker game. The hand he was holding aces & eights is known to poker players as what?