'ello, filling in for Huhh989 for the week. What new app did you find this week that you want to share? Addictive game, helpful tool, or something completely different?

Rules:

1. Please form your responses with: [OS] App Name that links to app store location.
2. ONE app only please. Do you like a few? Come back next week and submit your 2nd.
3. You can choose whatever OS you like. iOS, Android, OS X, Windows, whatever.

Example:

[Android] Puzzles with Matches-I like spatial brain teasers and wanted more stuff to play with-this fits the bill perfectly. Decent amount of non-trivial puzzles, good for killing time, and reasonably responsive/doesn't freeze up.

Source: grabworthy