I raided mom's recipe box to find this old recipe for making caramel corn in the microwave. I have not tried it myself, but several of us commented about remembering our moms making it this way, and said it was super-easy clean-up. Worth a try, I think.
Microwave Caramel Corn
Place 3 quarts of popped corn in large paper grocery bag that has been sprayed with nonstick spray.
In microwave-safe bowl, combine: 1 cup brown sugar, 1/4 cup Karo syrup, 1/2 cup margarine, 1/2 tsp. salt. Microwave on high for 2 minutes. Stir well. Microwave another 2 minutes, then stir in 1/2 tsp baking soda, mixing well. Pour over popped corn in bag. Close bag and microwave on high for 90 seconds. Shake bag and microwave on high for 45 more seconds. Pour into pan and cool. Store in airtight container.
(I believe the ingredients are exactly the same as my previous recipe, though only 1/2'd. Taste should be great, just not sure how it comes out...crunchy, chewy??) If someone tries this before I do, please let me know in the comments how it went. Sounds super simple and quick!