Vamos - Local Event Discovery

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.

ClockTweets - Schedule, analyze, and stalk challengers on Twitter

Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

Tweetastic - Better Twitter analytics, scheduling and more