Put a cap on each one to keep dust out and try to keep them as cool as possible to slow the yeast down until you can properly cap them. Even so, 12 hours without capping wont do too much to the end amount of CO2 you get.
Primary: Apfelwein, Raspberry Lambic, Experimental Wheat cider, IPA
Keg 1: Hefe
Keg 2: Irish Stout
Keg 3: Peach Kolsch
Keg 4: Empty
Bottled: Bourbon Vanilla Porter, Chocolate Stout