Please post below your must do orienteering events/challenges/moments, that either you have done, want to do, or would urge anyone with an interest in orienteering to do at some stage in their lives... Post a bit of a spiel too about why you think they are a must do, and I'll compile the best of the bunch for a guide at some point.
Have done:
Jukola/O-Ringen - The biggest events in the world for teams/individuals.
Fantastic organisation, brilliant atmosphere, great (usually) terrain, the sort of events that all other events should aspire to being as good as. Only complete with a post run cider in the sauna at Jukola.
Urge others to do:
In addition to the above...
Race at the Grand Bazaar (Istanbul 5 Days) - An incredible venue for a sprint race round the narrow lanes (watch you don't crash into anything outside of the stores!) and up and down the steps between the multiple levels in this ancient market.
and race round the City of London

Want to do:
Venice Street Race