Here is a List of the 54 Voice Remote commands. Add any more you know of!

[jerryez]

Here is a start from the Dish instructions, but it is not complete. You must press and hold the microphone button on the remote for these to work. Add any more that you know of and I will add them to the main list.
Voice Commands
Example Commands
Categories

• Actor: "Liam Neeson"
• Genre: "Movie"
• Movies: "Blades of Glory"
• Shows: "Big Bang Theory"
• Sport: "English Premier League"
• Sports Team: "Broncos"
• Year: "80s comedies"

Natural Language

• "Free movies starring Tom Cruise" (name of actor)
• "On Demand TV Shows from HBO" (name of network)
• "Show me movies I can watch now"
• "What live sports are on right now"
• (name of actor) "Johnny Depp movies from the 90's"
• "You can't handle the truth!" (other popular movie quotes)
• (name of actor) "Eddie Murphy movies rated PG-13 and below"
• (name of actor) "Movies with George Clooney and John Turturro"

Navigation

• "Tune to channel 140" (channel number)
• "Tune to Animal Planet" (name of channel)
• Launch VOD: "On Demand" (when watching a show)
• Launch Home Screen: "Home" (when watching a show)
• Launch Main Menu: "Main Menu" (when watching a show)
• Launch DVR: "DVR" (when watching a show)
• Open Guide: "Guide" (when watching a show)
• Page Up (in guide)
• Page down (in guide)
• Go to Live TV: "Live TV" (from delayed play, DVR playback, Menus, etc)

• Show Program Info: "Info" (when watching a show)

Configure Settings

• Picture in Picture On/Off "Picture in Picture" or "PiP" or "Swap" or "Side-by-Side"
• Set Recordings "Record this" (when watching a show)
• Playback "Play this" (when in the DVR screen)

Other

• "Skip Forward"
• "Skip Back"
• "Fast Forward/Rewind"
• "Pause/Play/Stop"