I'm Ben, the founder of Calibre (calibreapp.com) — A web performance monitoring tool. I'll spare you the product pitch now, but I'd definitely encourage you to take a look at Calibre if you're interested in making the web faster.
Last week we released (and open sourced) an app that pushes Calibre metrics received from a webhook to Geckoboard! (Using the Datasets API).
^ An example dashboard using Calibre metrics.
Otherwise, if you're looking to push some custom metrics into Geckoboard using Datasets, this is probably the repository that you want to fork!