Browsable database of third party intents?

To get into the spirit of Android, I'm looking for ideas of applications I could interface with.

I'm still learning android so my terminology is a bit lacking, but If I'm rig开发者_运维技巧ht, it's possible to define custom Intent actions and so forth, for custom data types, and the developer docs talk about apps interacting with one another.

How are developers meant to learn about each others' interfaces?

You can have a look at OpenIntents