for the hell of it
US /fɔr ðə hɛl əv ɪt/
UK /fɔr ðə hɛl əv ɪt/

1.
for no particular reason; just for fun or excitement
:
•
He decided to climb the mountain just for the hell of it.
•
I bought an extra ticket for the hell of it, in case someone else wanted to come.