Some days, it's simply good to be a nerd.  Whether its the perfect casting announcement, a day set aside to test-drive the hottest game, or a midnight screening of the next blockbuster, everything gets all tingly when the geek stars align. And align they have, for uber-nerd hottie, actor, creator and writer of 'The Guild,' Whedon favorite and Elf Goddess herself, Felicia Day has signed on for an upcoming episode of 'Supernatural!' 

TV Guide reports that Day will guest star in upcoming season 7 episode, the appropriately titled "The Girl With the Dungeons and Dragons Tattoo" as lowly a tech girl and amateur computer hacker working in one of Dick Roman's companies  "Charlie" inevitably finds herself wrapped up in Sam and Dean Winchester's problems, as "a classic  story of an everyday girl who does not want to be in a whistle-blower position."

For those unfamiliar, Dick Roman (James Patrick Stuart) has been the object of Dean Winchester's obsession as the season-long "Leviathan" big bad and the one to ultimately put a bullet in Bobby Singer (Jim Beaver)'s brain.  Says 'Supernatural' boss Sera Gamble of Day's casting, "We were so stoked that she agreed to do the episode because we're all fan girls and boys here."

Airing April 27, "The Girl With the Dungeons and Dragons Tattoo" is of course a reference to the insanely-popular Steig Larsson novel trilogy, and its acclaimed multiple cinematic adaptations, compounded by the fact that Day may be best known as computer nerd heroine "Codex" of 'The Guild'.  Before Day's appearance however, 'Supernatural' returns from a brief hiatus with this Friday's "Out With the Old" and continues with the highly publicized return of Misha Collins to the series in the follow week's "The Born-Again Identity."

What say you, Felicia Day fans?  Is this dream casting, or what?  Will you check out "The Girl With the Dungeons and Dragons Tattoos," or did you check out of the series after season 5?  Give us your take, and PG-13 thoughts on Ms. Felicia Day in the comments below!