It surprised me your not remembering my name.
I know, grammatically it’s absolutely fine (the example is taken from a dictionary).
But does it sound fine in informal conversation, as well? (Using colloquially the grammatical forms of such kind, I mean. As for me, it seems a bit too complicated and strained, but I’m not native.)
Could you say something about the grammatical forms and structure simplicity/complexity of colloquial English in the light of the above example?
I’d say the sentence is grammatically wrong, since it has two subjects, the first being the pronoun of the second: ‘it’ and ‘your not remembering my name’.
You could say however: “Your not remembering my name surprised me”. To me, it sounds a bit formal, though.
A more usual way of saying it could be: “It surprised me that you didn’t remember my name”, for example.
Conchita’s point of view has reasonable grounds. I totally agree with Conchita’s opinion
Hi!
Thank you, Conchita. This means that as I over-trust widely-used dictionaries, my right initial feeling that ‘something’s wrong’ with the sentence had realized in completely another question. 
And you gave an answer to the true question. 
Pamela, by the way, I’ve taken it from ABBYY Lingvo, you (also) use.
You can easily find the sentence in your version (installed on your PC), if enter
Empty subject: “it” and “there” and take a look at the examples given in 1(в) (ing- clause) -
with the comment “Such constructions are typical for colloquial language” (“Такие конструкции характерны для разговорного языка.”)
It would be interesting to have further opinions, especially on how this would sound to a native ear. I personally don’t think I’ve heard this construction before, not even in colloquial English. I normally (blindingly!) bllindly trust dictionaries, though, hence the shadow of doubt on my part.
Edit: I meant "I blindly trust dictionaries, not blindingly’ 
!!
Dear Amy
Do not tantalize us any more! 
Your opinions about the sentence???
Yours
Tom
Hi Tamara,
Your sentence:
is a bit of a dog’s dinner and as Conchita has already elucidated, there are simpler ways of saying the same thing. You could just say: I’m surprised you didn’t remember my name but it has been wrapped up into a mouthful. Grammatically it scrapes through because ‘your not remembering my name’ is in appoistion to ‘It’ and in that sense accounts for and explains what ‘it’ is.
Alan
Hi Tom 8)
As Conchita and Alan have mentioned, the sentence clearly means “It surprised me that you didn’t remember my name.” and that sort of construction would also be more typical. The more typical “that you didn’t remember” part has been transformed into the gerund form “your not remembering”.
Maybe also worth mentioning is the fact that many people would probably tend to be “ungrammatical” (informally/colloquially) and use “you not remembering” if and when they use that sort of construction.
Amy
Hi!
This is not the first time when ABBYY Lingvo (at now this seems to be the most widely-used Russian-English electronic dictionary) gives dubious examples. Pretending that they are ‘typical’…
It’s very important for such cases to have a feedback like you gave.
Thank you very much!
Tamara