That folder is for situations you save yourself. Set up a flight exactly how you like it, the go to File -> save situation to save a "snapshot" of that moment in time. Then you can use File ->load situation to go back to that exact spot later on. Please note that this file format is not very stable in v10 so .sit files saved in older versions (10.36 or 10.42 for example) may not work after you update X-Plane.
If you'd like to play one of the existing situations/scenarios, check out the Aircraft & situations screen. There are the options to drop from a B-52, glider tow, space shuttle re-entry, and more.