I've made it a few times now, using this recipe.
Here's a Europe friendly (metric!) version...
500g chopped rhubarb (that was about 4 stalks for me)
2 pie crusts (I use store bought puff pastries)
1. In a large bowl, combine the sugar, flour and cinnamon. Add the eggs and whisk until smooth.
2. Gently stir in the rhubarb.
3. Line a pastry case with the bottom pie crust and add the filling. Dot with butter.
4. Cover with the top pie crust and seal the edges together (the original recipe says "Trim, seal and flute edges". I've no idea what this fluting business is, but what I usually do is fold the excess top pastry under and pinch it together with the bottom pastry edge. Then press a fork on the edge to make it prettier... This works just fine).
5. Cut slits in the top pastry so air can escape while its cooking, and the top pastry doesn't go flying off... You should have something like this...
6. Stick it in an oven preheated at 205 degrees C (or 185 for a fan oven), for about 45 minutes. As for most things, keep an eye on it the last few minutes;)
And this is what you get!