Ceviche - w/ white fish and green olives
You can google for a recipe for ceviche + olives (a unique ingredient, IMHO).
Freshness of all ingredients is key for ceviche, and the amount of variations and varities you can come up is pretty much endless... You can use many different types of fish (boneless tilapia filets are great; salmon tends to let out a lot of water but is easily accessible and relatively inexpensive; definitely use what you can get fresh locally), and mix it with whatever salsa you care to make (in the summer you can use some really fantastic, knock your socks off heirloom tomatoes; also the type of onion used will change the flavor/texture, as well as the other ingredients of course). You can also alter the taste somewhat by whichever acid you choose to marinate with (lemon or lime, and different varities of each Key Limes versus Regular Limes, Meyer Lemons versus other types of lemons, etc. etc.).
The usual steps:
Small dice a firm fleshed fish
Marinate in acid (FRESH lemon or lime juice) for 20 mintues or two hours or more until fish is opaque.
Drain if it's too liquidy (as in the case of salmon)
Mix with a fresh Salsa that you've made
Serve immediately or let the flavors meld for a while.