From: Florian Frank on
There was a memory leak in the two previous versions that is triggered
by calling the JSON#generate method and friends. If you use the affected
versions, please upgrade to the newest version, 1.4.2.

The new version can be downloaded from these URLs:

http://rubygems.org/gems/json/versions/1.4.2
http://github.com/flori/json/tree/v1.4.2
http://www.ping.de/~flori/

Thanks to Dustin Schneider <dustin(a)stocktwits.com> for reporting the
problem.

Regards,
Florian Frank