Enter a probability or arithmetic expression that evaluates to a probability. Now think of a number, 1 to 20. A grid of numbers will appear and your number will be lit up with the given probability. Why's that useful? Say you owe me $7 but only have a twenty. Give me $20 with 7/20 probability. Perfectly fair in expectation!
The Beehive Collective of Obtuse Nerdtastic Tools created this application that falls into the Tools category. The most recent update of Expectorant was launched on Feb 8, 2011 and the app has been installed by over 1K users. According to the latest info, this application is rated 3.9 on Google Play.
It's free of charge to get the installation package of Expectorant, also, you can take a look at users' reviews on Droid Informer. The app works fine on Android 1.0 and higher. The app is completely safe for downloading.