Many foods can be prepared in the microwave, even if they're not specifically listed as microwave ready. All you're doing is heating up the material, that's called cooking.
If you do try something in the microwave, the best bet for success is this:
* Remove from it's packaging, the packaging may release nasty chemicals if it's heated, plastics especially.
* Go slow until you know what you're doing, I did some chocolate chip cookies in the microwave too long, after the water cooks out the sugar will start smoldering, and perhaps burst into flame (I didn't get THAT far). It smells REALLY REALLY bad if you smolder cookies!
Foods you can microwave that arn't listed as microwavable.
They will not brown, but they will fluff up and are VERY edible. I put mine in a 3in round bowl, and came out with a 1.5in tall pancake (bowlcake?). Our maple syrup was still sealed, so I used some honey instead, it was tasty! I also thought of taking a cup or scoop and hollowing out a hole in the middle of the bowlcake and putting a scoop of butter pecan icecream into it, YUM!
I like to make plate sized cookies, they real fun with a scoop of icecream. Cookies stick, I usually just scrape them off the plate and eat em with a fork, but if you're going to use them for something else you'll want to oil the plate or use parchment paper.
Grab a bag of bulk rice, it'll maybe cost you a dollar (microwavable rice costs $2 for much smaller packets). Put the rice into a glass bowl, add a tablespoon of butter, and melt in the microwave for 1 min (or you can use olive oil and skip this step). Then 'crack' the rice by microwaving for 1-2 minutes until it gently begins to brown, if you get dark brown, or black, start over it will taste awefull. Then add your water (1 cup of rice, 2 cups of water, etc) and microwave until the water is absorbed and the rice is cooked to your tastes. If it gets dry, add water, if it's too wet nuke it longer.
Quite possibly the best of all microwave foods. Remove the plastic wrap (ick!) Place upside down on a plate and nuke in 15 sec increments, eventually the filling will heat and squirt out like a volcano, when this happens the Twinkie is at the peak of it's flavor, and HOT watch out.