If you need to convert files from one markup format into another, pandoc is your swiss-army knife. Pandoc can convert between a wide range of formats.

Contextual unit and timezone conversion on any web page (units: several metric/Imperial, both ways, configurable; timezones: any timezone to your local time).

This public service is intended to provide simple functions to convert any vCard file into another format.

Converting OpenDocument to MediaWiki format