All Facebook reports that Facebook just sent out invites to an event in San Francisco on January 18th. It's a barebones invite without any imagery or hint as to what's going to be announced. Notably, it's being held at the 25 Lusk restaurant in San Francisco, not the Facebook's Palo Alto headquarters. Facebook's new Timeline has been slow to roll out since mid-December, and the Open Graph is still set for sometime in early 2012.
Facebook announces a January 18th event in San Francisco
Facebook announced an invite-only January 18th event in San Francisco, but offered few details as to what it will be.