The website for the forthcoming visit of Pope Benedict to Britain has a page that gives an outline of the vigil due to take place in Hyde Park on the Saturday afternoon/evening.
I have also seen a timing of 3pm-9pm for this vigil, so I expect that the vigil itself, as described on the Papal visit page, will be preceded by a kind of festival of dance, song etc.
That the culmination of the vigil is a time of Eucharistic Adoration, with Benediction of the Blessed Sacrament, is really quite striking. It reflects the precedent set at World Youth Day celebrations, with the vigil with the Pope the evening before the closing Mass also being centred on a time of Eucharistic Adoration. I recall Pope Benedict observing early in his pontificate that he saw it as a sign of providence that he was elected to be Pope during the Year of the Eucharist initiated by his predecessor. That a time of Eucharistic Adoration comes at what I suspect will be a kind of turning point, a kind of lynch-pin event during his stay in Britain seems entirely appropriate.
In other respects, the three part structure of the vigil and its objectives are, in my view, very well thought out. The idea of showcasing how the Catholic Church contributes to the common good, to what "new Labour" would have called a "public benefit", is both politically and ecclesially sound.
If you have not been able to obtain a ticket to take part in the vigil, there is no excuse! There will, I think, be opportunity to greet the Holy Father in the streets and at least to be somewhere in the park with a Papal flag ...