If you've been hanging around the Bikram community for any length of time you probably have heard that you should not wear green when taking class from Bikram himself. Do not have green shorts or top on. Do not bring a green mat. Do not have a green towel, hand towel, washcloth, water bottle, hair tie. In fact, if you have green eyes, close 'em! (just kidding about the eyes)
As you may know, Bikram's guru was Bishnu Ghosh. Bishnu's eldest son died in a fire trying to save his friend, that unbeknownst to him, had already gotten out. He was wearing a green shirt that Bishnu told him not to wear because it was considered bad luck.