Indie adventure game The Journey Down, which has actually been available in various versions for a while now, but today sees the release of a "HD" version which turns the formerly low-fi experience into something a little shinier.
If you've never played it, but love adventure games, you should see about fixing that. Of all the games in the last 20 years to have tried, The Journey Down probably does the best job of all in capturing that special mix of humour, puzzles and quirkiness that made the 1990s the golden era for the genre.
It's playable for free, but if you like what you play I'd say pay the $US14 and get the HD version (available below). It's definitely worth it.
The Journey Down [Official Site]