This is sad news to say the least. Google Notebook is an extremely useful tool for personal organization. It also feels disturbing that Google will discontinue its great services one by one.
One feature I have always wanted from Notebook is the ability to add items through GData. I guess this will never be added.
I have found HTTPBuilder to be incredibly useful in Groovy. Shouldn't it be named HttpBuilder?
Anyhow, I used it to script calling an HTTP service. I was having a few issues with the get method until I started using 'params' instead of 'query' as the Google example is doing. The documentation is sparse so likely I was misusing this facility.