* Spoilers ahead. Tread carefully. *
The most obvious starting point is that the Pandorica is related to Pandora’s Box. So when the Pandorica opens, it should be something like the opening of Pandora’s Box; all the bad things escape and only hope is left. Given the numerous references to fairy tales and myths this season (the Doctor says Amelia Pond is like a name from a fairy tale, Jeff’s computer is labelled M¥TH, et cetera), further myth-inspired plot developments should be a fairly safe assumption.
Just a thought: 'The Medusa Cascade' derives from Greek mythology. 'Pandorica', apparently, does too.
Here are some references to Greece's language and/or mythology.
- The 'MΨTH' laptop and heart monitors - Ψ being the Greek symbol for Psi;
- And River Song's 'Ω' on her epaulette, the Greek symbol for Omega;
- High Gallifreyan appears to be 'a mixture of Greek letters and mathematical symbols'.
If you wish to see pictures of the references mentioned above, please go to http://www.digitalspy.co.uk/forums/showthread.php?p=40856083. This is the site which contains the information regarding Greece.