On the French version of Reims tourist office website you’ll find events calendar for the following months.
The English part of the website doesn’t show these documents just recall the main events in Reims city (which are many)
Once you have downloaded these documents you ‘ll have to have notions of French or use internet tools to translate them.
Here is a link to the calendar events section: link
These versions have been downloaded early in August but may have been updated meantime. Please get them from the tourist office in Reims. December 2011 is published so you may already check events related to Christmas market events and animations in Reims.