ilo - Premium Twitter analytics
Calendify - Calendify is an event community where you can share, publish, and subscribe to event calendars. It helps you to stay informed about what you are interested in and what is yet to come.
Tweetastic - Better Twitter analytics, scheduling and more
Morse - Create, shout out, and discover nearby events in real time
Twitter Interactions - See all your interactions 💬 with other Twitter🐦 users
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.