An end pour is a mass of thickened epoxy poured into the ends (bow and stern) of a kayak to re-inforce them. Since a large mass of epoxy will heat up a lot as it cures, many people will put a garbage bag over the end of the kayak to keep it dry and then stick it in a big bucket of cold water. The kayak is usually leaned up vertically against the side of your house when you do this, but some people have holes in the ceiling of their garage.

Here's a pretty good site that shows an endpour about halfway down the page. http://junior.apk.net/~jimkozel/Kayak/

The trick is to pour the epoxy down into the very end of the kayak. To do this, many people fill a paper cup with thickened epoxy, and lower the cup through the cockpit with a string. Another string fastened to the bottom of the cup can tip the cup once it is in place at the bottom (end) of the standing kayak.

You don't need a lot of epoxy to do an end pour. One paper cup full should be enough. 6-8 ounces or so.