If like me you aren't very good at pumpkin carving then let your kids just draw on them with a sharpie pen.
It's so easy and they love it.
Then just put them on your stoop, window ledge or front door.
The easiest and cheapest decorations are cob webs.
I get quite a lot of cobwebs (glow in the dark) available from any pharmacy (USA)
Get the kids to help you.
Spread them out really well across railings and doors attaching to anything that sticks out.
Don't just clump them it doesn't look real.
Then throw a handle full of plastic spiders on top!
These are some photos I took last year around our neighborhood in Brooklyn New York.
This is one of my favourite houses.