What occurs twice in a week, once in a year but never in a day?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Usually, a boxing match consists of twelve rounds. In a particular friendly match between two heavyweights, the match was finished in the ninth round itself as one of the boxers knocked out the other one.

But, in that fight, no man threw even a single punch.

How can this be possible?

What goes up but never comes down?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

John was piloting a plane behind a car but was never able to overtake it. Why?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

What has many keys but can’t open a single lock?

Give it food and it will live; give it water and it will die.

When I asked a girl's name she told me her name is the date '07/09/2001'.

I thought for a few seconds and then I got her name. Do you?