Hapen - Shareable reminders for the world
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Tiny Reminder - Collect content & files from busy clients
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Birthdays Reminder - So now you can finally delete your Facebook account
Bigtent - BigTent is a web-based organization and communication portal for groups.