Taxatoy is an application that graphs the number of new species discovered every year, from 1750 to 2000. The graph can be filtered by taxon using the dropdowns at the top, and the green timeline.
Taxatoy's graphs are fully interactive. Use the dropdowns along the top to filter the graphed species by the taxonomic tree. Use the green timeline to zoom into a particular place in history. You can also zoom by dragging a selection box directly on the graph.
The data behind TaxaToy can be downloaded as an Excel Workbook.
TaxaToy exposes a resourceful REST API which you are welcome to use. All data is serialized in JSON format. It's pretty simple, watch the XHRs in Firebug to see how it works.