Foldable blue/green screen from Serious Magic
The blue or green screen is used for Chromakeying, which is one of the most often used special effects in the movie industry. Chromakey software digitally replaces the blue/green color with a background. You saw great use of chromakeying in Star Wars and Spy Kids. The background can be either a static picture or video.
I carry around a foldable screen which is green on one side and blue on the other. This gives you some flexibility as to what color your subject can wear.
Another alternative is to just paint a whole wall green. Rosco Green paint is specially designed for Chromakeying. It is possible to have your local hardware/paint store mix you up a batch of green paint, but make sure it is matte finish instead of shiny. Have a nice long talk with your significant other before doing this!
Lighting will make or break a video shoot. If you are on a budget, Home Depot style halogen worklights will do the job. Your actors may feel like they are standing on the Sun with that much light pointed at them.
Normal lights, which include the worklights, will cast shadows everywhere. Professionals use "softboxes", which are lights enclosed in a cloth box. The cloth diffuses the light, so it doesn't cast as much shadow. Think of light going through a shower door and you will get the idea.