Clashes between protestors and Central Security Forces (CSF) erupt in Tahrir Square and the Interior Ministry.
There are conflicting accounts of how these clashes began, described here: http://english.ahram.org.eg/News/15315.aspx
What is certain is that relatives of people killed in the revolution went to Cairo's Interior Ministry where they say there were attacked by CSF. The demonstration then grew into a protest against the tardiness with which former regime figures are being held to account. Several protestors I spoke to said that they feel "nothing has changed" after January's revolution.