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

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.

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

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.

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.

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

HOURGLASS - female, because over time, the weigh 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.

REMOTE CONTROL - female... Ha! You thought I'd say male. But consider, it gives men pleasure, he'd be lost without it, and while he doesn't always know the right buttons to push, he keeps trying.