In VIM, how do I break one really long line into multiple lines?

Question

Say I have a super long line in the VIM editor (say around 300+ characters). How would I break that up into multiple lines so that the word boundaries roughly break at 80 chara

Answer 1

I needed to reformat an entire file rather than one line. As Wernsey points out, I could have used 'fmt', but the following sequence in vim did the trick also (borrowing from the various answers here):

:setl tw=80 fo=t
1GVGgq