If you don't think your gang is up to eating a whole bunch of rapini at one sitting, just blanch the lot (the rapini, not your family) and it'll be ready for you when you want more without the hassle of prepping it again.
Simply put a large pot of water on to boil, cut off the rough ends of the rapini, rinse it clean, then add the jolly greens to the boiling water, along with a couple of teaspoons of salt, for 2-3 minutes.
When time's up, dump into a colander and rinse with cold water until cool. Drain, squeeze out extra water, towel dry, then store in the refrigerator until ready to use in a recipe. (If you plan on eating it plain, blanch for 4-5 minutes.)
One of the most common preparations of rapini is doing it up Italian-style: To a large skillet add 1-2 tablespoons of olive oil, heat it up and add a couple of thinly sliced garlic cloves to the oil. Let them crisp up (but not burn). Throw in a half teaspoon of red pepper flakes, then a blanched bunch of rapini cut into bite sized pieces. Add salt and pepper, toss it around for a minute. Done.