Host Not Responding?

I'm not getting a response from the Google Calendar API.  Once in a
while I get a status 500 response.

I'm doing a plain POST, with Email, Passwd, source, and service as form
data, and I'm using the URI
https://www.google.com/accounts/ClientLogin.

This used to work, but now it doesn't.  Am I missing something obvious,
or is there an issue with the service? (Yeah, I know how dumb that
sounds...)

(11:45 a.m. Eastern, 8/25/06)