LinkedIn, Twitter, eHarmony, and Last.fm recently fell to hackers, and now it's League of Legends' turn: the popular free-to-play action RTS is reporting a security breach. According to Riot Games' Marc Merrill and Brandon Beck, the specific security issue has already been fixed, but not before hackers accessed a number of databases in the EU: email addresses, account passwords, name, and dates of birth were all accessed, and could well be in the wrong hands by now. The company insists that "absolutely no payment or billing information of any kind" was included.
Players in affected regions should get an email informing them that their data was compromised, but you should probably change your password right away. In the meanwhile, you can read how Riot promises to continually safeguard your personal information at the source link, and draw your conclusions from there.
Update: As commenter Kaggy notes, League of Legends was also allegedly involved in an incident last year, where LulzSec allegedly brought down the game's authentication servers with a distributed denial-of-service (DDoS) attack.