Our API directory now includes 54 calendar APIs. The newest is the InfoPark Web Calendar API. The most popular, in terms of mashups, is the Eventful API. We list 47 Eventful mashups. Below you'll find some more stats from the directory, including the entire list of calendar APIs.
Expedia recently announced the expansion of its API portfolio. The new API includes integration with in-destination, local activity suppliers. The API is included within the larger, legacy Expedia API environment and enables significant upsell, cross-sell, and broader partner possibilities.