Two legendary mistake fares are based on this.
Travelocity got their XPF:USD conversion ratio wrong by two orders of magnitude, so tickets originating in Tahiti went on sale (back in 2005).
Numerous airlines didn't implement the IATA memo describing the floating of the Myanmar Kyat, and consequently, fares based on the fixed MMK:USD rate were quite reasonably priced post-devaluation (last year).