I think Spam gets kind of a bad rap sometimes -- if you prepare it well, it can be really tasty! Here's one of our favorite recipes, which also happens to be the easiest (and cheapest) way I've found to make Reuben sandwiches.
1 can Spam -- sliced
1 loaf Pumpernickel -- sliced
1 can sauerkraut
1 lb. block Swiss cheese -- slice as many slices as you have Spam slices
Heat sauerkraut in a small kettle. Fry spam on a griddle, adding a little butter if necessary. Butter two pieces of bread for every slice of spam. Layer ingredients on bread and fry as though it were grilled cheese.