The cast and crew of Dr. Horrible's Sing-Along Blog (2008) perform a "most uncommon" musical commentary track for the show, acting as exaggerated versions of themselves. After reviewing the circumstances that led to the creation of Doctor Horrible, the characters sing of the contrary and cheap Joss Whedon, the aspirations of the minor actors, the egos of Nathan Fillion and Neil Patrick Harris, and everyone's favorite iPhone game.
| Actor | Role |
|---|---|
 Neil Patrick HarrisNot listed | Not listed |
 Nathan FillionNot listed | Not listed |
 Felicia DayNot listed | Not listed |
 Simon HelbergNot listed | Not listed |
| NNick TowneNot listed | Not listed |
 Jed WhedonNot listed | Not listed |
 Rob ReinisNot listed | Not listed |
| OOtto Michael PenzatoNot listed | Not listed |
 Steve BergNot listed | Not listed |
 David FuryNot listed | Not listed |
 Marti NoxonNot listed | Not listed |
| SStacy ShirkNot listed | Not listed |
 Maurissa TancharoenNot listed | Not listed |
 Zack WhedonNot listed | Not listed |