This is a toughie..can understand your problem.
1.My number one would be the crusades since this may well be pertinent to what is happening in the world today.
2. How about explorers?There was a lot of exploring done then. I admit a lot more was to come but you might be able to lay some foundations.
3. Science..people like Galileo, Newton etc. still have relevance today.
4. I think a study of catholicism and how religion and politics were co-existant in Europe.
5. I know this is a bit out there but what about a study to show how little things changed for ordinary people in that 1000 year period. Even though globally things were happening the living conditions of the peasant remain virtually unchanged. Squalor ruled.
6.Lastly...hmmm...how about the impact of the romans on civilistaion...what they contributed and if their legacy lived on after their demise.
Ok just a few ideas..hope you get something out of it. I know i really enjoyed coming up with stuff. Hope you get more answers here.