The parts needed for this instructable are:
1x 10x4 piece.
3x 2x4 piece.
1x 8x1 flat smooth piece.
1x 1x4 flat smooth piece.
2x 1x2 flat smooth piece.
1x 1x20 (make up from smaller pieces)
1x 1x22 flat (to go on top of the above)
1x 1x2 with pin sticking out of the side.
1x 2x20 (make up from smaller pieces)
1x 2x22 flat (to go on top of the above)
1x 2x2 with pin sticking out of the side.
1x 4x22 (just make it out of 4x2 bricks and you're fine)
See the picture below, on the left is the base, middle is the walls and right is the top.
Note: the flat bricks aren't in the picture because I'm lazy.