Do you have an iPhone? Would you like to play Myst for free? You can, sorta! What used to be the Myst demo is now called Myst FREE [iTunes link]. You can explore Myst Island, but that’s about it.
Meanwhile, this post is, shall we say, bare, because I’ve never played Myst. I have no idea what it’s about, other than that it was/is a big adventure game. I also don’t have an iPhone (or iPod touch) so I’m SOL on this one.
The full game [iTunes link] is $4.99.