Yeah, well your mom was really good last night 

A comeback, usually signifying that the person saying this phrase can't win the argument.

"Go fuck yourself, you piece of shit whore"
"Yeah, well your mom was really good last night"

Yeah, well your mom was really good last night by Assholes Inc. September 10, 2003

Yeah, well your mom was really good last night 

1.The universal comeback*.
2.The comeback to end all comebacks*.
3.The most overly used comeback ever.

*in theory

"Well. . .Your an asshole. . .asshole."
"Well, Your mom was really good last night."
"Dammit"

Yeah, well your mom was really good last night by Fatass February 13, 2003

Yeah, well your mom was really good last night 

Ok if you leave my mom out of this
Ill leave this <point at ur member> out of your mom!

ComeBack for most your mom jokes

Yeah, well your mom was really good last night by GUY November 27, 2003

Yeah, well your mom was really good last night 

a comeback

"Cracka I just whooped yo sorry ass in that game of checkers. BOOYAH BITCH!"
"Yeah, well your mom was really good last night."

Yeah, well your mom was really good last night by Nick D February 13, 2003

Yeah, well your mom was really good last night 

Another alternative would be "Your mom was easy"

<Hickery> Haw haw! I pwnz0red j00 in teh Chess!!!1!!1!!2 j00 is teh too easy!
<Dickery> Well, your mom was easy.
<Hickery> Oh my!

Yeah, well your mom was really good last night by Bastardized Bottomburp September 1, 2003