If you are getting tired of eating the same types of sashimi I highly recommend you try Nate Bakers Carpaccio recipe. One of my friends requested ponzu at our last party so I looked it up and it's super simple.
you will need:
fresh yellowtail or some decent grade of raw fish (that is not a freshwater fish unless you want parasites)
ponzu sauce (bottled or if you want you can make it from scratch but you'll have to look it up on the net)
smelt eggs (masago)
cut green onion
Cut the yellowtail into thin slices and plate it. Mix up the ponzu with a dash of syracha (to taste). Pour this mix using a teaspoon over the fish. Take a separate spoon and sprinkle smelt eggs on top of that and finally add the cut green onion. Serve immediately.
Nates recipe is the second plate from the left, the ponzu is the third plate.