Many historic timezones have 15 minute offsets. In the era before American railroads synchronized timezones to the hours, Louisville, KY, as one example close to home, was often UTC-5:45. (It's GE's fault that Louisville and consequently most of the US I-65 corridor wound up EST rather than CST.) I don't expect to win arguments that the city should return to UTC-5:45, but I make them anyway to amuse myself.