What makes a good task?

What is a task, anyway? A task is "any language learning activity that the students do in their classes" (game, comprehension questions, gap-fill exercises, etc), says this article by Andrew Littlejohn.

I like some of the questions the article poses:

• What is the aim of the task?
• Where do the ideas and language come from?
• How personally involving is the task?
• What happens to what the students produce?
  

We might also ask who the ideas and language come from -- from the teacher or the learners?

In a second part of the article, Making good tasks better, Littlejohn suggests that we can "improve a task if we can increase the amount of ideas and language that the students are expected to produce" -- in other words if it's not the teacher providing all of it.

In a third article on Language Learning Tasks and Education, the same author asks other questions that I think we should ask ourselves when designing classroom tasks.