An extremely cheap tactic, that has worse vibes then rushing.

-Scout your opponent early with a probe, and make sure your opponent doesn't see it. Leave the probe in his base away from his vision for now.
-Build a pylon and a forge in YOUR base as soon as possible.
-While the forge is building, build a pylon right out of your opponent's vision, outside of his workers.
-When that pylon is done, build 2 cannons very close to it.
-When those are done, go into his vision and start to build cannons.
-Your opponent will go "what the?" and try to attack them, but the 2 cannons you built earlier will take care of any attackers.
IMPORTANT: Don't forget to build some cannons in your base too!
After those cannons are done, everything will go boom boom boom. Continue building cannons to destroy his whole base. Also, build a gateway, so in case he tries to run away, you can build some zealots to chase him down.