It's the simplest planner available. Users type plain-language commands into Coolendar—no need for precise syntax—hashtagging keywords to organize similar tasks. For example, "Monday, 5 p.m., don't forget to pick up the #dry-cleaning." Coolendar automatically slots these into a to-do list and will send Gmail and Google Talk reminders. The free site syncs with other calendars and has an app for smartphones.