The Airmap Elevation GeoPoints Curl Sample Code demonstrates how to access the API to return an array of elevations matching the array of given GEO Points. Points is the parameter and it associates with an array of latitude and longitude points.
Shoudio is an amusing iOS application made to tag places with audio snippets. These can be anything a user imagines, and a lot of fun could be had with this. For example, integrating this into Geocaching could be a lot of fun, allowing things like audio hints to help Geocachers find the cache. However, the developers of Shoudio didn't want it limited to just one platform, so they released a Shoudio API to allow clients for other platforms, and fun mashups.