I've been using this glider to teach general science skills for some time, and so many colleagues have reacted positively to it, I thought I'd share it with the wider world.
Don't worry; if you only want to learn how to make the glider, I'll make the educational parts obvious so that you can skip over them.
I may be boasting, but this glider is one of the simplest, and most elegant gliders I know. I started out using more complex gliders in lessons, but I found I was spending more time teaching how to make gliders than I was working towards the lesson objectives. Over time, I simplified the glider to the point where learners refuse to believe it will fly, until they see it in action.
Start with a rectangle of paper. For convenience and scale, I typically start with a sheet of A6 paper - a normal piece of A4, cut into four parts:
That's it, you're finished. If you've made it right, you should have a piece of paper, curved like a gentle smile, with a folded edge sitting on top of the smile.
If you find you cannot make a curved glider fly straight, you can, instead, switch to a single crease down the centre of the glider (see the last photo). This option also makes step 7 a bit easier.