I've been very interested in trying some Infrared photography after seeing some beautiful examples at sites like http://irbuzz.blogspot.com/. Jerry, has a wealth of information to get you started with this medium and for less than $60 I was able to grab a Hoya R72 filter and headed out to the mountains to try and catch the turning of the leaves.
Jerry has a great introduction to IR photography here, but in a nutshell, IR is in the spectrum of light beyond the range where humans are able to see with the naked eye.
Graphic courtesy of: www.maxmax.com
Most digital cameras have what is known as an Infrared Block or Hot Mirror Filter that allows visible light but prevents IR light from reaching the sensor. If you're a serioues IR nut you can open up your camera and have the filter removed. However, even with the block a small amount of IR light reaches the sensor. Therefore a much less daunting alternative is to buy an IR filter for your lens (Hoya are a recommended brand) and use a tripod and long exposures to capture static scenes.
While I was a little late to catch the leaves turning in the mountains (most of them had fallen already) I was able to take a few shots which ended up with an eerie quality that was quite apropo for halloween.
Hope you enjoy them, it's great to add a new technique to your repertoire and I think this opens up a whole new area to explore.