invalid date format in specification: "2011-08-25 00:00:00.000000000Z"

This is an annoying problem with the outdated Ruby installation on many of the Debian/Ubuntu apt-get.

Invalid gemspec in [/var/lib/gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z"

One fix is to upgrade to ruby1.9 but I don't want to. What if it messes up my other configuration? A quick way is this:

sudo sed -i 's/ 00:00:00.000000000Z//' /var/lib/gems/1.8/specifications/*

This solution is taken from here. But every time when you install a new gem (pip package, in Python's world), the problem will appear. But it's safe to do it again.