The calendar app space is getting even hotter with new competitors launching every day, each with its own idea of how your calendar should work in the age of "the cloud." Some, like Tempo, aim to "intelligently" supplement your calendar with email attachments, phone numbers, and maps. Sunrise, on the other hand, syncs effortlessly with Google Calendar, brings in Facebook events, and lets you instantly text friends on their birthdays. Another entry is UpTo, which launched version 2.0 for iPhone on Thursday (with an Android update on the way). It's the first calendar we've tested that easily brings in events shared by friends, your favorite sports team, or upcoming movie release dates.

When UpTo launched back in 2011, it focused on helping you see what friends had planned in the future. Version 2.0 hopes to be more like the calendar app you're already using, but with the ability to subscribe to any of 5,000 external "streams" of events from concert venues, to TV shows, to Canadian national holidays. Any company or individual can build a stream using their current calendar subscription URL, or by manually inputting events. In other words, you can subscribe to the Detroit Tigers stream instead of manually adding events for all the games you want to watch.

A calendar app injected with shared events from friends and sports teams

UpTo also lets you add close friends and family to your friends list, so when they add an event, they can opt to share it with you (and vice versa). For example, if your younger sibling adds their college graduation to their calendar, one tap shares it with close friends and family. The event will show up in your calendar, at which point you can tap "I'm in" to add it to your calendar, or swipe it away. You can comment on shared events, and if somebody responds, you'll receive a push notification. Of course, UpTo also lets you choose specific groups or people to share an event with, if you'd like.

Setting aside its social features, UpTo works well as a calendar app, but doesn't include many of the "contextual" bells and whistles many of its competitors tout like information about the people you're meeting with, or quick-add events like in Fantastical. The app feels a lot like a souped-up version of the native iOS calendar, and even uses iOS's event editing screen if you want to add repeating events or change alert times. Yet, while Sunrise and Tempo feel futuristic in the contextual sense, UpTo's social features feel futuristic unto themselves. It should be easy to share an event with a friend without technically "inviting" them like you have to on Google Calendar. It should be easy to subscribe to your favorite team's schedule or the public calendar of the city you live in. UpTo understands this, and while it might not be the de facto "best" calendar app, its social virtues make it a compelling alternative.