Elly May?
This part of Modern Family script
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P: It's like Steve Jobs and God got together to say, "We love you, Phil."
C: What's so great about that doohickey?
P: "Doohickey," Elly May? It's a movie theater, a library, and a music store all rolled into one awesome pad.
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I found Elly May is a actress,
but what's the meaning in this situation?

Question

Elly May?
This part of Modern Family script
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P: It's like Steve Jobs and God got together to say, "We love you, Phil." 
C:  What's so great about that doohickey?
P: "Doohickey," Elly May? It's a movie theater, a library, and a music store  all rolled into one awesome pad. 
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I found Elly May is a actress, 
but what's the meaning in this situation?

Answer

"Elly May" was a character on the American situation comedy "The Beverly Hillbilliies":

http://en.wikipedia.org/wiki/The_Beverly_Hillbillies

"doohickey" (like "thingamajig" or "thingamabob") is an unsophisticted word to describe a contraption/machine you don't full understand. By calling "C" "Elly May", "P" is making fun of "C", saying that "C" sounds like a "hillbilly" or unsophisticated person talking about something like an iPad, I imagine.

Answer

Actually, it's a character: Elly May Clampett, from the TV series The Beverly Hillbillies.  Elly May is a country girl, so a little uneducated in the ways of the city.  "Doohickey" would be a typical country-person word for an invention or device.