Check out Lego Universe! It's got the MMPOG of WOW without the content issues. Well, you do destroy some stuff but it's not really violent- no more than any LEGO game where the bits all roll around and it's over.

If that's not what you're looking for, look at JumpStart World. There are tasks and jobs to do, games to play and it also has learning games up to 2nd grade level.