Just for fun, I'm curious about how native speakers do mental translation from Gregorian calendar year (e.g 2011) to Japanese era name 年号 (e.g. 平成23年), and vice versa. Do you have special and preferably fun ways like mnemonics or children songs (something like the ABC song) to help you do the translation on-the-fly?
p/s: Due to subjectiveness of this question, I'm totally fine if this is made into community wiki.