GreekChat.com Forums - Nouns and gender

From the Washington Post, in which it was postulated that English should
have male and female nouns, and readers were asked to assign a gender to
nouns of their choice and explain their reason.

The best submissions:

COPIER -- female, because once turned off, it takes a while to warm up.
Because it is an effective reproductive device when the right buttons are
pushed. Because it can wreak havoc when the wrong buttons are pushed.

SWISS ARMY KNIFE -- male, because even though it appears useful for a
wide variety of work, it spends most of its time just opening bottles.

KIDNEYS -- female, because they always go to the bathroom in pairs.

TIRE -- male, because it goes bald and often is over-inflated.

HOT AIR BALLOON: male, because to get it to go anywhere you have to light a
fire under it. And, of course, there's the hot air part.

SPONGES -- female, because they are soft and squeezable and retain water.

WEB PAGE -- female, because it is always getting hit on.

SHOE -- male, because it is usually unpolished, with its tongue hanging
out.

ZIPLOC BAGS -- male, because they hold everything in, but you can always
see right through them.

SUBWAY -- male, because it uses the same old lines to pick people up.

HOURGLASS -- female, because over time, the weight shifts to the bottom.

HAMMER -- male, because it hasn't evolved much over the last 5,000 years,
but it's handy to have around.

What are some examples you would submit?