here's an easy one that keeps for a week in the fridge:

Green Olive Tapenade
from Bon Appetit

In a processor:

1 10-oz. jar green olives, pitted (pimentos removed)
1 2-oz tin anchovy fillets, drained
2 cloves garlic, chopped
1 heaping teaspoon capers

Process until finely chopped. Scrape bowl and add

1/4 cup olive oil

Process to a purree Season to taste with:

cayenne pepper
Lemon juice

Serve with toast or crackers, and it's great with seafood.

(I slice up a baguette thinly and dry them out at 325* for about 1/2 hour, brushiing with olive oil halfway through. This makes very crisp toast that will keep for weeks in a zip-lock bag.)

another Tapenade (from Richard Olney)

8 oz. pitted Kalamata olives
4 anchovy fillets
1 clove garlic, mashed with a pinch of salt
3 Tablespoons capers
A big pinch of savory
A small pinch of cayenne
1/4 cup olive oil

Make the same way as the one above. The two are nice together.