Here's what you'll need:
a lunch size paper bag
1/4 cup of popcorn kernels
a pat of butter or margarine
Dump the kernels and butter into the bag (I probably only use a Tbsp of butter) and then fold down the top of the bag twice.
Cook in the microwave for 2 minutes - you might need to adjust the time depending on your microwave. Once I hear the popcorn slowing down, I turn off the microwave, but leave the popcorn in. Usually it's hot enough that a few more kernels will pop :)
Now you can season your popcorn and enjoy! Sometimes we use the butter spray and other times we use butter seasoning - it all depends on your preference. My grocery store carries a white cheddar seasoning that I'm dying to try!