Ask HN: Best way to keep up to speed on a new language/technology quickly?

[flotblot]

For those that have successfully learned a new language, framework, etc. from zero to an intermediate or expert level very quickly, how did you do it? I typically learn by experience at work, but I don't have that luxury this time.

[factorialboy]

* Join the community mailing list, and be active

* Try to solve the 99 problems with that language - http://www.haskell.org/haskellwiki/99_question

* Try writing (book / blog / articles etc.)

* If its open source, participate in the community, fix issues, send pull requests etc.