According to a statement on a company splash page, GitHub, a site where software developers host and collaborate on their code, came under a large distributed denial of service attack, a common hack used on large databases. Used by many large software companies, the site is the backbone of the software development community, and is often a target of hackers.
The attack was focused on the site's storage, and has took away those capabilities along with code downloads. While the site has come back online, it seems that some capabilities are still limited.
At present time no one at GitHub has replied to requests for a comment on the attack.