Doorknob it is

Well done you doorknob saavy people! Yes, the kid comes out in me...I prefer simplicity to long drawn out thinking. But it is a good riddle, dontcha think? What goes through a door, but never goes in or out!? Hm... Amazing how much we use the little creatures every day!

Once again...apologies...my pda won't let me edit my post...but the handy-dandy Mail-to-Blogger now lets me post via email...what will they think of next?!