Sure, it's easier just to zap a bag of the stuff, but, really, where's the fun in that? Try making it the old-fashioned way next time, and follow these easy instructions.
First, you need some popcorn. Jolly Time is probably the most widely known brand in the States, so it should be easy to find at your local market. However, shop around and try different brands and varieties for some fun.
Make sure you store the kernels in an airtight container. Popcorn depends on a certain amount of moisture to pop, and an airtight container will help the kernels stay fresh.
Likewise, you should never store popcorn in the refrigerator or freezer as this can cause excess moisture, as well as fscking up the amount of time the kernels take to pop.
Use approximately 3 tablespoons of oil (vegetable, olive, Crisco, whatever) to just cover the bottom of a heavy pot with a lid (a 3 quart pot is about the right size).
Now pour in just enough kernels to cover the bottom of the pot (about 1/3 cup if you're using a 3 quart pot). Cover the pot (but leave it somewhat ajar to let steam escape, thus preventing tough and/or wet popcorn), put it on medium heat, and shake the pot from time to time to send unpopped kernels to the bottom.
When popping stops or slows, remove from heat. Uncover carefully, place in a large serving implement.
Season to taste (I like a little Tabasco, a little salt, and Parmesan Cheese).
Sure, it takes a bit longer than microwave popcorn, and you might burn a batch or two, but what a sense of accomplishment you'll have when you finally whip up that bowl of freshly popped popcorn for your family and friends.