The Orange Revolution of the winter of 2004-2005 in Ukraine was a series of grass-roots, non-violent political protests that involved hundreds of thousands of people demonstrating in the capital city of Kyiv.
The database containing the results of the Ukrainian presidential contest between Viktor Yushchenko and Viktor Yanukovych had been compromised, and international observers who had conducted exit polls questioned the numbers.
During the protests, the SBU (Security Service of Ukraine) exercised restraint in their policing and avoided bloodshed.
The protests succeeded in forcing a revote that led to Viktor Yushchenko being elected president of Ukraine.
"Ukraine's Orange Revolution" by Andrew Wilson 2005 Yale University Press $22 ISBN 0300112904