Android app stress testing. Monkey.

http://developer.android.com/tools/help/monkey.html
You'll need an emulator or an ADB-connected device.
It's a command line utility. To start it:

$ /Users/Username/Library/Android/sdk/platform-tools/adb shell

Start pushing events (an example for 500 events):
monkey -p your.package.name -v 500

Enjoy your phone's life:)