I had one rule going through college and for open parties when inevitably I was approached to use the system for dances; sorry, but No.
Unless you have full control of the system, and even if you do have full control, attempting to broadcast to the neighborhood is a good way to damage your speakers. It's one area of enjoyment of sound to which I would never subject my gear. If you're going to do it, go get a pair of cheap Insignia speakers or something from Craigslist or garage sale, so that if the worst happens it's a laugh and not a cry.
If you want to show off, bring people you trust into your home to show them the rig. You might discuss it first and see if they have interest. If not, let it go.