Simple Syrup is one of those things you'll see popping up in recipes from time to time.
It is very versatile, adds that "little something extra" to many recipes, and is really easy to make.
Proportionally:
Light Syrup = 2 parts water to 1 part sugar
Medium Syrup = equal parts sugar and water
Medium Thick Syrup = 2 parts sugar to 1 part water
Thick Syrup = 3 parts sugar to 1 part water
The technique is the same for all of them, put the ingredients into a heavy bottomed saucepan, heat over medium heat til the mixture comes to a boil, and all of the sugar has dissolved.
After the syrup is made, it may be flavored, things like flavored extracts (vanilla, almond etc.), liquors/liquers (framboise, grand marnier, poire williams, etc), Espresso, anise seed,..just about anything
Syrups are crucial ingredients to many cocktails (i.e. almond syrup for Mai Tai). Plain or flavored syrup is the best thing to sweeten iced teas and coffees with. (I love iced espresso with vanilla syrup and a touch of cream).
Plain simple syrup is crucial when making fresh lemonade!
I would never ice a cake without brushing it with an appropriately flavored syrup. It adds moistness, and keeps the crumbs in place as you frost.
Anyhow, they are just really versatile ingredients, that alot of people don't even know about. If you want specific recipes, I'll be happy to post!