For the first time ever Bethesda have announced an E3 press conference of their own on Sunday June 14 (via Bethblog). Apart from the obvious (!) press invites they are also inviting fans to register for a few select seats at the conference.
No word yet on what to expect, but obviously the fact that Bethesda have a press conference lined up seems to suggest they plan on revealing some major or perhaps a series of big announcements. Fallout 4 comes to mind. And the new Doom that has gone off the radar for a bit.