From Heroku:

http://status.heroku.com/

Over 20 Amazon instances failed at the same time today. All app operations are offline while we recover from this distributed failure. All data is fully backed up. We expect app operation to be restored within the hour.

Our service has been down for about an hour now. Looks like our cloud computing service www.heroku.com is down. We may switch to our Amazon instance if Heroku doesn’t come back online soon.

Thanks for your patience.