Eventful API

From their site: Eventful is the leading events website which enables its community of users to discover, promote, create and share events throughout the world. The Eventful Demand service enables users to create grass-roots campaigns to demand events and performances in their city. In addition to event discovery and promotion at Eventful.com, the underlying technology platform enables sharing, feeds and event data syndication to other websites, blogs, calendars and partners. The same platform upon which Eventful.com is built is available to developers to build upon: go here to read about our Developer API.

Overview
Summary	Events discovery and demand
Category	Events
Tags	events music concerts calendar
Date Added	2005-10-31
API Home Page	http://api.eventful.com/
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Protocol
Protocols	REST
Data Formats	XML, JSON, YAML
Service Endpoint	http://api.eventful.com/rest/
Functionality
API Groups	Events, Venues, Performers, Users, Groups, Demands
Example API Methods	/events/new, /venues/get, /users/search, /events/performers/add
Client Install Required	No
Security
Authentication Model	Basic with username/pass in query string, MD5 Digest
SSL Support	No
Read-only Without Login	No
Support
Vendor API Kits	Perl, PHP, Javascript, Python, Ruby, Emacs Lisp
Community API Kits	.NET, Cold Fusion
API Blog
Site Blog
API Forum
Developer Support	Mailing list (with archive)
Signup and Licensing
Signup Requirements
Developer Key Required	Yes
Account with Service Required	Yes
Commercial Licensing	Upon request
Non-Commercial Licensing	see API Terms of Use
Data Licensing	upon request
Usage Fees
Usage Limits	30,000 requests per day (excluding /*/new or /*/add)
Terms of Service	Eventful Terms of Service