My dad cut this out for me from the paper. It is a hoot:

Freezer bags: They are male because the hold everything in, but you can see right through them.

Tires: Tires are male, because they go bald easily and are often over inflated.

Sponges: These are female, because they are soft, squeezable and retain water.

Hot Air Balloons: Also a male object, because to get them to go anywhere, you have to light a fire under their butt.

Web Pages: Female, because they're constantly being looked at and frequently getting hit on.

Trains: Definitely male, because they always use the same old lines for picking up people.

Egg Timers: Egg timers are female because, over time, all the weight shifts to the bottom.

Hammers: Male, because they've hardly changed in 5000 years and are occasionally handy to have around.

Those are cute, will have to copy them and send em out to my friends who aren't on this site.