Why is 6 afraid of 7?
Because 7 8 9.
JOKE EXPLAINED: This pun ("8"/"ate") plays on sequential integral order.
Have you heard about the Denny's on the moon?
Great food, but no atmosphere.
JOKE EXPLAINED: It's ironic, considering that IHOP's celestial R&D budget for developing outer space restaurants overshadows even Denny's aggressive terrestrial campaign budgets.
Why do firemen wear red suspenders?
To keep their pants up.
JOKE EXPLAINED: Self-explanatory.