I like to find simple solutions for terrain since having it around is such an important part of wargaming. Many people don't make terrain since they think it is too hard, too expensive or any old pile of crap will do anyway. To the contrary, I think decent terrain can be had cheaply, easily, and thematically. This technique can be used for just about any game system, just change the template a bit and you are good to go. For this project you will need:
2 Sheets of black foamcore
2 Empty cereal boxes
Here is how to make the razor wire (sorry no pics ATM): Take two lengths of wire, one thick and one thin. Wrap the thin one around the thick one like the design on a barber pole. Once you get to the desired length, clip off any excess. Take the wrapped pieces of wire and wrap them around your pencil, creating a coil. Remove pencil and you are done!
Keep in mind you can buy a very nice plastic version of this set up for about $300, if you want. This cost me 15 bucks.