Anyone have any samples of using AuthSub in asp.net

Hello,
I'm writting a small application that display google calender data in
different ways. I have it mostly written using the google api for c#.
I've been using setUserCredentials() each time I make a request, and
resend the usersname and password for authentication.

I have that this is not proper authentication mechinism for webapps. I
was directed to the api docmentation for AuthSub. I can't find any
usage examples for authsub though.Does anyone have any usage examples
using asp.net or tips?

Also I read that when using AuthSub, this sends the user to a google
login page and then sends the user back to your app after it is done. I
really don't want to do this, is there a mechinism to just take the
input from your own form and send it off to google to get a token?

Thanks for any advice,
Rob