
Ragnar said that
if you refuse his CHALLENGE,
Vikings Season 1, Episode 6

Surely there are others out there
who still dare to CHALLENGE my reign.
Game of Thrones Season 4, Episode 2

...as they CHALLENGE
the preconceptions of the fields.
The Big Bang Theory Season 2, Episode 4

Go old-school,
CHALLENGE Stuart to a fight.
The Big Bang Theory Season 5, Episode 10

Challenge me, kraken.
Game of Thrones Season 4, Episode 2