Assumed knowledge: a rudimentary understanding of composite nodes, and how to render a video.
This is a simple tutorial on how to make a custom sequence wipe. It used to be a fairly complicated process to do this, but with nodes, it's quite easy.
You'll need three video strips as inputs. I decided, to make night transition into day, with a rotating, scaling octagon as the wipe. The reason the sun and the moon are upside down, is because they are rotating and about halfway through the sequence. So, anyway, to begin:
Make 3 videos. I'll call the first one ' vid1' and the second one 'vid2', and the third i'll call the 'mask'. I'm going to make them each 101 frames long.
The first and second, can be of whatever colors, and composition you want, but the mask, make black and white, and make it transition from solid black, to solid white. I did this by making my white octagon, scale from very tiny, to slightly larger than my camera view, so, solid black, to solid white. be creative, like teeth, or spirals, or whatever, if you'd like. Make the white object 'shadeless' for the purpose of this tutorial.
Now, open a nodes window, delete the render layers node, because you don't need it, and add 3 image nodes, a mix node, and you should already have a composite node. if not, add one.
In your first image node, load vid1, and set the frames to 101
in the second, do the same with vid2
In the third, do the same with the mask
Now connect the 'image' outputs of the first two image nodes to the 2 'image' inputs of the mix node, and connect the 'image' output of the third image node, the mask, to the 'fac' input of the mix node, and connect the 'image' output of the mix node to the 'image' input of the composite node.
Now set your frames to render 1 - 101, press the 'do composite' button, and press 'animate', and there you will have it, hopefully. Here's a look at my nodes window.