Any variety of arugula will work, as will any other peppery green for that matter; dandelion greens or cress are great substitutes. And of course basil or parsley work, too. As for the pasta, if you don't feel like making your own, any store-bought will do. I'd choose orecchiette, fusilli or gemelli.
Put the garlic and pine nuts, plus a pinch of salt, into the mortar and pound it until the bits no longer jump out of the mortar. Add some of the cheese and some of the arugula a little at a time and keep pounding and mixing with the pestle. Keep doing this until you have a pretty good paste. Grind in the lemon juice, then drizzle in a little olive oil and keep grinding and pounding. Keep doing this, little by little, until the pesto is the consistency you want: You'll need between 1/4 and 1 cup, depending on how loose you want the sauce.
ALTERNATE METHOD
Put the pine nuts, garlic, salt, cheese, arugula and lemon juice into a food processor and buzz into a paste. You will need to scrape down the sides of the food processor a couple times. Then, drizzle in the olive oil with the motor running until you have a sauce the consistency you want; loose for pasta, tight for bread.
Cover the pesto with a layer of olive oil, or set plastic wrap directly on the pesto's surface (this prevents the arugula from turning brown), and set it aside at room temperature before eating.
Notes
Drink a dry rosé or a crisp white wine with this. For beers, go with a pale ale, a session IPA or a wheat beer. And actually, this is pretty good with macro beers like Bud and Coors, too.