I love acorn squash, but not everyone has a field of veggies to eat in their back yard. In my mind, squash is one of the easiest vegetables to cook. You simply cut it half. Scoop the seeds out (save those for roasting). Then put the halves in a pan, cut side down, and roast.
Bake in a 350 degrees F (175 degrees C) oven until it begins to soften, approximately 30 to 45 minutes. Remove squash from the oven and turn onto a plate so that the flesh is facing upwards. Place butter and brown sugar into the squash, and place remaining squash over the other piece.
http://allrecipes.com/video/329/how-to-make-baked-acorn-squash/
If you are like me and have a tendency to forget things are in the oven, put an inch of water in the bottom of the pan and cook the halves with the cut side down. It gives you a little safety.
This is the traditional way to cook almost any squash. There are so many ways to use these babies though. I love them stuffed!
http://www.foodnetwork.com/videos/guys-roasted-acorn-squash-0222682.html