Answer
$720$
Work Step by Step
The number of ways to select the first joke: $6$ (any of them can be )
The number of ways to select the second joke: $5$ (any of them can be apart from the first)
The number of ways to select the third joke: $4$ (any of them can be apart from the first and second)
The number of ways to select the fourth joke: $3$ (any of them can be apart from the first, second and third)
The number of ways to select the fifth joke: $2$ (any of them can be apart from the first, second, third and fourth)
Then the last joke is the one that is not the first, second, third, fourth or fifth.
Number of different ways to schedule the appearances:$6\cdot5\cdot4\cdot3\cdot2\cdot1=720$
