You probably think you know what I'm going to say here, don't you? (Hint: Don't be fooled by the photo above!) You think the answer is a paper bag. And that's not a far-off guess, but it's not correct. (I told you not to be fooled by the photo!)
Paper bags are really great for making microwave popcorn, but if you make popcorn as much as we do in my house, all those paper bags are going to get pretty wasteful. Even if you reuse them a few times!
If you want to go the paper bag route: How To Make Popcorn in the Microwave
The red part is silicone and has many key features that help during the popcorn popping process. It starts off as a measurer — it has markings on the side to help figure out when to stop pouring in the kernels. It also has vents to let out the steam, and reinforced handles that will stay cool to the touch. And it stays on tight when shaking the kernels up with butter, salt, or other toppings.
When you're done shaking just put the whole thing on your counter, upside down, and the BPA-free plastic popping dome becomes the bowl. After cleanup, the two pieces nest for storage.
I love this guy because it's easy to use and also because it really does seem to get almost every kernel in the bowl popped (in my house, that's very important).
Buy: Microwave Popcorn Popper, $25 at OXO
Prefer to make your popcorn on the stove? Here's the best tool for that job.