Grand Rounds was conceived as a weekly hosting event which features the best posts in the medical blogosphere. Several outgrowths of the "original" Grand Rounds have appeared recently, arranged mainly by subspecialty or location. I do not think that they will dilute the Grand Rounds "brand" and they may be interesting to follow. A list is compiled below:
Grand Rounds (original). I have hosted it twice, it was fun and an eye-opening experience.
Radiology Grand Rounds
Change of Shift: A Nursing Blog Carnival
Pediatric Grand Rounds
The BritMeds - this is the latest carnival. Dr Crippen would like "this round-up to be be strictly British. Otherwise, the criteria will be relaxed. British blogs written by anyone working in healthcare or anyone receiving health care in this country."
BlogCarnival.com has a longer list of many health-related carnivals.