Since you're probably not going to make it I'll skip the recipe - it's basically lamb organ meats (heart, liver, lungs, kidneys, etc) mixed with suet, onion and oatmeal ... stuffed in the stomach of a lamb, and boiled for a couple of hours. The oatmeal works as a filler and it does produce a "sausage" kind of thing. My grandmother made it a couple of times I actually liked it! Of course - I was young and didn't know it should be "yuckey".
Go to www.google.com
and do a search on haggis and you can find recipes.
Actually - it sounds much worse than it taste.