Try the battery slot of your stereo... hide it in your pillow... hell, fill one of those boxes with something innocent (legos, artwork, underwear) and put the pipe at the bottom.

a lot of the times, the most obvious places are best. like if my parents are comin and my bro has to hide shit real quik, he puts the bong behind the curtains, and just sets the bud on his desk. they never even look