Calendar! is a free Android application developed by Yutaka Tsumori. As the name suggests, it is a calendar that can be conveniently displayed in the notification area of your device. One of the unique features of this app is that it displays the upcoming schedule up to 4, making it easier for you to plan your day.

Another useful feature of Calendar! is that you can run any application when you tap the notification. This saves you time and effort from having to navigate through your device to find the app you need. However, it is important to note that due to the limitations of AndroidOS, the icon cannot be hidden.

Overall, Calendar! is a convenient tool for those who want quick access to their schedule and frequently used apps. It is easy to use and provides the necessary information at a glance.