City spectacles entertaining school on vacation (4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

O O (two zeros = spectacles, especially in cricket where “a pair of spectacles” or just “a pair” means a player’s score of zero in both innings of a match), containing (entertaining) S [choo] L (on vacation = after emptying = inner letters removed). Capital city of Norway.