P2Do is a free to-do list manger, and task calendar. P2Do is an easy-to-use software to create your to do lists, organize them in form of calendar, and segregate items by using categories, and tags.
P2Do comes with an extremely easy to use interface. You just start typing in the editable box to create a new task. Then you can assign a category to it, and also assign a tag.
Apart from that, you can assign a due date to the task. Then you can see the task in the integrated calendar that comes with P2Do. You can directly add a new event via calendar as well.
P2Do also lets you assign relative priority to various tasks.