Puzzle from pi: Crossing a river

Although there was no Dev Patel, or tigers in this pi, we still managed to squeeze a boat into this week's puzzle.

This puzzle is a variant on an old favourite. We don't have chickens, corn, or foxes, but we still want to cross a river. Here's the question:

A husband and wife come to the edge of a river, where they find two children with a small boat. The boat can hold either one child, two children, or one adult. How do you get everyone across the river in the minimum possible number of crossings?

Post your answers below, and we'll give you the answer in the next podcast!