The Spike or Grob Opening line begins with the strange appearing 1. g4. Most players would not think of making this move in a game of chess that they want to win. It damages king side pawns with an unguarded advanced pawn. The Grob opening does offer many tactical advantages for white though along unusual opening lines.
After using 1. g4, follow with 2. Bg2 and depending on your opponent's reactions, 3. c4. These odd moves will send your opponent's head reeling with trying to figure out what in the world you are thinking. Your opponent's may even think that you are obviously inexperienced and will not even take this opening, or you, seriously, which gives an automatic advantage.
One difficulty with playing chess against more experienced players is that they have a common response to common openings. Every time you use a certain opening they will respond with a certain defense that has worked for them in the past. This is where the Grob comes into play, since it is so unusual for someone to use it, opponents are often unsure of how to respond to it. The Grob opening is particularly useful in speed, or blitz, chess games.
The Grob is also effective in chess games that are not timed. The Swiss correspondence master Grob used his namesake to win many different correspondence games. In this case, a B-Class player defeated a strong master with the Grob. Try out this unusual opening in your games and see if you can make it work for you. It does give you, as white, certain tactical advantages whereby you can exploit blacks responses when your opponent is unsure of how to respond to such a different opening.