It depends on if it's just the three of us or if we're visiting my family. If we're visiting family we play Dirty Santa, there's a huge Christmas Eve spread (turkey and ham sandwiches, cheese and crackers, dips, chips, chili, and lots of cookies and other treats), and there's usually a Chirstmas Eve type program where everyone can read a story or poem, sing or play a Christmas song (lots of musical talent in my family which sadly escaped me), and sometimes there will be a Christmas play, and then the reading of The Christmas Story from the Bible. We finish the evening with PJs for all the kids, hanging up the stockings and putting out cookies and milk for Santa and carrots for the Reindeer, before sending the kids to bed.
If it's just the three of us we do everything but the Dirty Santa and Christmas program, and we usually watch a Christmas movie or concert instead.
I really love both Christmas Eve's, I love the big family get together, but sometimes the less stress and quiet of it just being the three of us can be pretty great as well.