School Project House Design, Help Thank You?

Hello, I'm a school student, so I'll get straight to the point, my teacher asked us what we wanna be later in life and me and 5 others who said architect, got an assingment to digitally design a house, and other kids got projects on their intrests, my problem is the teacher told us there are lot's of free program's on the internet that are easy to work with to digitally design a house, can you please me help me out with where I can get one of these free easy to use programa's the project is due monday but I really need to start working on it. Thank You so much!!School Project House Design, Help Thank You?
check this program








http://sketchup.google.com/

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