Post date: Oct 13, 2011 10:15:31 AM
Gnome calendar applet adheres to your locale settings. In Ubuntu, you can assign locale components by editing the file /etc/default/locale.
LANG="en_US.UTF-8" LC_TIME="sk_SK.UTF-8" LC_PAPER="sk_SK.UTF-8" LC_MEASUREMENT="sk_SK.UTF-8"
Important setting is LC_TIME. If you want english names, use en_GB.
Thanks to this post.