I cut chard into 2" pieces. Toss the stems into a large shallow pan with 1" salted water. Cover & cook for a couple of minutes, then add the leafy tops. Cook until just tender. Drain & set aside. In the same pan, heat to medium with several tbsp olive oil and 1 or 2 cloves very thinly sliced garlic, a handful of halved kalamata olives, and a tbsp or two of chopped preserved lemon. When fragrant, add the drained chard. Toss around for another couple of minutes until heated through. Taste & adjust for salt & pepper.

This is a lovely recipe for a vegetarian main dish or a side for roasted or grilled meat or fish.

http://www.food52.com/recipes/7884_savory_swiss_chard_tart

i like to keep it simple: olive oil, chili flakes, thinly sliced garlic. to make a heartier meal, i also sometimes add sausage removed from it's casing. either way, you can always put it on top of pasta.

This is my favorite way to prepare chard, I only use about 3T. olive oil.
http://www.epicurious.com/recipes/food/views/Roasted-Garbanzo-Beans-and-Garlic-with-Swiss-Chard-241110

I am more than a little addicted to this:

http://www.food52.com/recipes/9947_chard_onions_pasta_and_an_egg

I have a couple over at my blog, "A Pound Of Yeast" (http://apoundofyeast.blogspot.com/). One is for stuffed chard leaves (think stuffed grape leaves) and one is for chard pancakes, where the shredded chard is mixed into a savory pancake batter, and then griddled like a pancake. Look in the archives, because I posted them a while back. I can vouch for the quality of both recipes, I've made them multiple times. And I was never a chard fan before I found these two.

This recipe is delicious prepared with chard instead of beet greens: http://www.food52.com/recipes/602_pink_greens