This, from the European Council on Foreign Relations, seems to me a pretty good five sentence summary of what happened at Maspero Square on October 9th, 2011:
The Christian victims of the Sunday massacre in the Cairo district of Maspero died a cruel death, many of them under the treads of military vehicles. . . . There is no doubt that State TV did incite the populace against the Copts, already under attack by thugs. . . . Police and troops were sent to Maspero to quell the riots – and the State TV broadcast appeals to “honest Egyptians” to rush to the scene and defend the Army, allegedly under attack by Copts. Dramatic footage of wounded military personnel was shown. Crowds flocked to the scene, and the riot turned into a massacre.
And here’s a bit more (again, from the European Council on Foreign Relations):
It started with an attack of sword-wielding thugs on a thousand-strong Coptic demonstration against an earlier attack on a church in Aswan. The church was allegedly illegally built; in Egypt it is allowed to build a new church only if the old one is crumbling down. This early attack, unfortunately, is hardly news; in Egypt, attacks on Copts are almost the norm.