It's been a tradition in our family for going on eight years now that each Summer, we provide movies on our garage for the neighborhood. It started out as a last-minute "Hey, wouldn't it be fun if..." moment. The first night, we had one other family over. Word quickly got out, and 8 years later, we now regularly have 60+ neighbors over to watch a movie with us. We affectionately call it "Movie on the Garage", and we generally kick it off the first weekend after school finishes for the year. That was last week for our school district. Now that Summer is in full swing, we'll schedule a neighborhood "Movie on the Garage" about every 3 weeks (give or take). We love it and the neighborhood loves it. It's a great way to socialize (and keep the kids out of trouble).
I still find it amusing when people are amazed at how simple my setup is. My philosophy with anything is this... don't overcomplicate things. So yeah, my setup is simple, and perfect. Quick to setup, and quick to break down after. Here's what I use:
First, you need something to play the movie from. I chose to play them from my Apple iPad w/ Retina. I never have to worry about the battery running out, it's super simple and why not? I actually think a laptop is too complicated and cumbersome. The iPad was made for things like this.
Next, I use a Mitsubishi projector. You don't have to use a Mitsubishi projector, but it's what I like and feel comfortable with. A relatively decent projector will run you about $1,000 or more. If you already have one, great. If you're looking for one, definitely consider one that offers widescreen (which is what most movies are these days), and the higher the ANSI Lumens (i.e.: brightness) the better.
Next, I use an Apple HiFi self-contained speaker. Remember those? Apple made these for about a year back in 2006 before pulling the plug on them. I still don't know why they did. I love mine! It works great, and again... it's super simple to use. I plug it into power (I can even run it off size D batteries, if I want to), and then connect the audio. That's it. Is it loud enough? Plenty loud enough for 70-90 people, even outdoors. I place it right in front of the garage, and that helps to push the sound forward. Brilliant and simple. Of course you don't need to use this speaker, but I recommend something as simple to use. There are plenty to choose from, and they'll run you about $300 or so.
Lastly, you can't forget the treats! We usually have popcorn, a drink of some sort, and even ask the neighbors to contribute with their favorite treat as well. Makes for a great party!
I usually set up about 45 minutes before it's dark enough to play the movie (which is about 9:00p right now). This gives me enough time to comfortably set everything up (which takes about 10 minutes), then play some fun music for the kids playing at the park across the street as they get ready for the movie.
As far as the cabling goes, I use an HDMI cable from the iPad to the projector (HDMI has both audio and video), both of which are located on a table about 20 feet from the garage door. I then run a long audio cable from the projector to the speaker, which is sitting in front of the garage door. That's it!