Vamos - Local Event Discovery
Maker Swipe File - 100+ high-performing Tweets to help you grow your audience
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.
Narrow - Narrow helps you build a targeted audience and increase your influence on twitter.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Tweetflick - Save, organize & find Tweets to get the most out of Twitter