Everyone writing a research paper or looking to resolve an argument this afternoon was SOL after Wikipedia suffered an outage.
Protocols to redirect traffic to servers in Florida also failed, causing the site to go down globally for a short time, Wikipedia reported in a post on their blog:
Due to an overheating problem in our European data center many of our servers turned off to protect themselves. As this impacted all Wikipedia and other projects access from European users, we were forced to move all user traffic to our Florida cluster, for which we have a standard quick failover procedure in place, that changes our DNS entries.
However, shortly after we did this failover switch, it turned out that this failover mechanism was now broken, causing the DNS resolution of Wikimedia sites to stop working globally. This problem was quickly resolved, but unfortunately it may take up to an hour before access is restored for everyone, due to caching effects.
We apologize for the inconvenience this has caused.
As of now (4:45 pm EST) Wikipedia is working normally in New York, but there may be some scattered difficulties reaching the site as information propagates across the internet.