Wonderful idea,
Holbytlass 
If the stores do run out, we can turn to cannibalism.
More details on the siege:
Board up the lower windows with planks from the garage so they cant be broken through.
Pour boiling water, the cheap substitute for oil, onto the orcs from the upper windows.
Throw antique lamps and other such parental belongings at the orcs. Perhaps set them on fire first.
Play loud rock music
Especially Blind Guardian.
Hm... I think I need more detail. What did the orcs bring? If they have siege weaponry I'm in trouble. I'm presuming they just have their little scimitars and swords?