Presently, the Calendar control for asp.net ajax does not offer such a functionality. Another option in this case would be to provide the details for the items, associated with a given date, in two grids. The grid control does expose a drag and drop behavior, as demonstrated in the following article:
I hope this suggestion helps.
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items.