The pumpkins are great, but they don't really do anything without a conductor. 

On the hardware side of things, there are 4 components that live inside the weatherproof outdoor box for my shows: 

• An amplifier
• A Raspberry Pi 3
• A 12V PSU for the audio speakers
• A 5V PSU for the Raspberry Pi and Pumpkins

Additionally, I have a distribution terminal strip to get power to a couple of places, and the Raspberry Pi has a USB "sound card", that provides sampling for the audio. It turns out that you can either multiplex the lights or the audio, but not both on a Pi 3. The sound card was an inexpensive solution. (It's worth noting that the BeagleBone Black, for instance, doesn't have this problem. It has plenty of PWM) I'm not sure if the RasPi 4 or 5 do)

I got an old grounded computer power cable (typical NEMA 3-prong to C13 cable) and cut off the end to make a pigtail. I crimped on some appropriate fork connectors, and screwed them in to terminal strip. I ran those into my 5v PSU, and the 5v signal out to the terminal strip where it'd be accessible.

The Pi, and the cable that gets 5v to the pumpkins get their power here. Additionally, the pumpkin cable has a third signal line that it connected to a blade connector that plugs into the Raspberry Pi (Pin 6 is available for the PWM)

The 12v power supply gets a C13 pigtail that connects to the terminal strip as well. (Coincidentally, I have one I just cut off a NEMA cable!) The barrel connector on the other side goes into the amplifier.

The amplifier takes an 3.5mm stereo out of the RasPi USB sound card, and provides speakers with 16AWG stereo lines.

I mounted all of this onto a piece of wood using various 3 parts. In some cases I extended existing models I found to mount. In others, I just designed something all together.

The wood base with everything on it goes into a Weatherproof box. I bought a medium-sized SOCKiT box, which fit everything I needed into it. 

In order for there to be a show, you have to have something to run the show. On my RPi I use Falcon Player (or sometimes Falcon Pi Player) 

FPP runs a daemon on the RasPi and provides an interface for specifying, uploading, and scheduling your light shows, and has become a mainstay of the light show hobby community. Though most folks use it for Christmas Light shows, it works just as well for Halloween :)