I've been playing Contradiction (http://store.steampowered.com/agecheck/app/373390/) recently.  It has been a lot of fun.   If you've never seen it or heard of it, it is an all video murder mystery where you investigate the death of Kate Vine.  It has a neat cast of diverse individuals (James is my favorite) and a nice unfolding mystery.

To play, you basically wander around the town looking for clues and talking to suspects.  When you talk to a suspect they sometimes give you items that you can ask other suspects about expanding the number of statements that each suspect has given.  You advance the story by finding contradictions in statements that a character has made.  The contradiction either exposes more statements (that then themselves contain contractions) or yield a new piece of evidence, which can be taken to others (generating more statements/contradictions).

Things I really like about it:

It is possible to play as a group.  A group of us all gather around the TV (I display the laptop on the TV) and all give suggestions and try to spot contradictions.  It is a great group game.  Some of the topics are mature (although nothing gory or anything is shown onscreen, only talked about) so it isn't a game for children.

There is a neat hint system where you can call the Chief and he will give you clues about what who might be lying if you are stuck.  Then there is another option to turn the clue into a spoiler if you are really stuck, so you never get to a point where you can't advance the game.