Iraqi Kurdistan constitutional referendum happened in 2009.

Abyei status referendum happened in 2011.

Egyptian Holiday - 2011 was released on:

USA: May 2011

East Timor passed an independence referendum in 1999.

South Sudan passed an independence referendum in February 2011. As of April 26, 2011 a name for the new country has not been decided. Independence is already set for 9 July 2011.

Constitutional amendments. (different countries will have different ways of doing this, some by popular referendum others by a vote of the legislature).