at the weekend BrE
on the weekend AmE

At the weekend, he would just watch television all day.

Tell him he can come over at the weekend instead.

He had to get his energy back at the weekend.

Here's a picture of him I took at the weekend.

So this was part of the job at the weekend?

Things started so well at the weekend I knew it could not last.

I hope that everything will go well at the weekend.

I'd probably use most at the weekend but it doesn't work then.

I just saw a number of them in a collection at the weekend.

He thought it over for a minute, and decided to go down at the weekend.