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

ParkingForMe - Marketplace for listing and renting unused parking spaces

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

On Air Parking - Ridiculously cheap and simple airport parking.

Bigtent - BigTent is a web-based organization and communication portal for groups.

Blucar - On-demand parking at the drop of a pin