The Grob (1. g4) is a much maligned opening but one of our members (who shall remain nameless as this post may be seen by prospective opponents) is rather fond of using it and has had a surprising amount of success with it.
He may like to know that he is not alone as a fan of the opening and that it has received strong support at high level, as can be seen in this YouTube video:
https://www.youtube.com/watch?v=_N62hul3EyU&feature=emb_err_watch_on_yt
Tommy Opposite