The release date for the second OVA, Negima! OVA Summer Special
has been set for November 22. This is a surprisingly quick release considering it's only a month after the release of the Spring OVA (October 25), and the fact that the Summer OVA screening hasn't taken place yet.
As with the Spring OVA, there will be two discs, one for the feature presentation and the other for a behind the scene extras, including voice dubbing shooting and coverage of the Summer OVA event, to be held on Sept. 17 (incidentally, I received the invitation to it by mail today).
Here is the synopsis for the Summer OVA. Beware! Spoiler warning! (Spring OVA synopsis here