Funny thing is I did BASE64 a password. Sort of. I used to run strong passwords + random stuff on paper through SHA-2 with result encoded in BASE64. Optionally an extra iteration or two for SHA-2. Used BASE64 because it fit the max number of characters for TrueCrypt passwords: my use case for this method. Had a tool to make this easier.

Idea was to obfuscate a strong password to make cracking more difficult. Plus, it was relatively easy to implement on arbitrary computers. These days I just memorize them or write them on paper.