Malaysia Airlines currently is either slashing their fares into the toilet or has mistake fares on many routes to/from Southeast Asia in September & October. According to a thread on Flyertalk, people have seen many fares as low as $15 USD each way for flights between a number of cities in Southeast Asia. Additionally others have found round-trip fares to Japan and Paris for around $365 from Southeast Asia. (Mostly KUL & SIN.)
As with most mistake fares, these probably won’t last long so if you are going to be in the area I highly suggest checking out the Flyertalk thread and searching for yourself. These fares should be bookable on the Malaysian Airlines website and Cheapoair. Additionally you can credit these flights to their OneWorld partners such as American or US Airways. You can find a full list of fare classes and how they earn on OneWorld partners in the thread as well.
HT: Drew from Travel Is Free