The machine itself (the model I have) is a brown rectangle, with Faux Woodgrain stickers on the long sides, and a cartridge slot on one of the shorter sides. There's a built in power supply, so there's a power cord running out of the back side. On the top, there are two gold stickers running the length of the long sides, surrounding the two controllers that are nestled in the middle. There's a power switch and reset button in one of the corners. The controllers are definitely the quirkiest thing about the Intellivision. The two controllers are hardwired to the unit by coiled brown cords (think telephone) and are approximately 3" x 6"- and only 1/2" thick! On the top half of the controller, there's a small keypad with the numbers 0-9 and also 'clear' and 'enter' buttons. Again, think telephone. On the bottom half, there's a gold disk- this is the actual movement unit. And, on both of the long sides, there's two buttons near the middle. The handiest way to hold this controller is to cradle it in one hand, use a thumb to hit the side buttons, and then use the index finger of the other hand to use the disc and keypad.
Intellivision Cartridges came in cardboard boxes that had a front flap that swung open, with the instructions tucked into a slit on the flap, along with some plastic overlays that fit over the keypads on the controllers. The cardridge is 2 3/4" x 3 1/2", and has a tapered end with the label on it.