As promised, here's a little more about my Halloween projects for 2009. The above is a pic of the bar - set up with a black light ($12 at Target), some cheap glow-in-the-dark skeletons and spiders (from the Dollar Store) and some carefully arranged tonic water (did you know the quinine in it makes it glow eerily under a black light? Apparently, a lot of people did know but it's news to me). 
Above is the crazy Halloween headress that I made with a headband, silver ribbon with wire, scraps of purple fabric, and cheap plastic critters from the dollar store (painted with silver craft paint). I used safety pins to put it together so it easily came apart and didn't damage the head band.
I call this look "fun with spiders". The big spider in the middle is crumpled newspaper, taped into a ball with packing tape and covered with crepe paper. The web is more crepe paper and the baby spiders were cut from black construction paper and taped all around the room.
The coffin decoration is admittedly rustic looking but was mostly a way to try to cover the two tall bookshelves in the living room. My books are too colorful and cozily cluttered-looking to be spooky. I cut the coffin shape from cardboard and used low-odor spray paint to paint them black. I added the "R.I.P." because I wasn't sure you could tell it was supposed to be a coffin; I know that coffins typically don't have RIP on them but I think it worked.
This spooky wreath cost very little to make. I bought a weird straw wreath at a thrift store for a buck and covered it with black crepe paper streamer. You could used a foam wreath or buy one of those cool black wreathes made especially for Halloween. A little bit of spooky ribbon, some fake flowers in appropriate colors, a plastic skull from the dollar store, an old necklace, and some fake cobwebs complete the look. I did use hot glue to affix the skull to the crepe paper but everything could be removed easily, if I wanted to re-use the wreath for another purpose.
Above is our homemade mummy (serving as the warden here, to Melanie's prisoner garb at work). He was made out of crumpled newspaper balls (for the head, chest, and hips) connected together (more packing tape) with cardboard tubes from rolls of gift wrap (I knew they would come in handy some day!) for the arms, legs, and spine. Melanie worked hard to wrap him in white crepe paper and misted him with a very diluted mix of water and brown paint to give him an authentic ancient look.
I think this one above is my favorite project. I found the frame at a thrift store and knew I could do something creepy with it. I stained the wood with silver acrylic and printed some creepy pictures off the web. Voila! Sometimes you just have to be on the look out for strange items and used your imagination to make them fit your theme!
