LOST has recently introduced Missing Pieces. Basically they are just 2-3 minute episodes that are from Season 1 & 2. You'll see what I mean.
http://losttrailers.blogspot.com/That contains:
Mobisode 1 - "The Watch"
Mobisode 2 - "The Adventures of Hurley and Frogurt"
Mobisode 3 - "King of The Castle"
King of The Castle isn't in high quality yet, I'll post the HD version when it's available.