If you need to display a calendar on your blog for bookings or events then there are a number of WordPress plugins that have got you covered - in this post I will take a look at the free and commercial options for you.
Ajax Event Calendar
This plugin allows authorized users to add, edit (as well as visually move and resize) and delete events in a community calendar viewable by all blog visitors. The calendar can be added to a page or a post using the "[calendar]" shortcode.
Ajax Event Calendar »
Events-Calendar is a versatile replacement for the original calendar included with WordPress adding many useful functions to keep track of your events. The plugin has an easy to use admin section that displays a big readable calendar and lets you add and delete events.
Events Calendar »
Event Calendar 3
Manage future events as an online calendar. Display upcoming events in a dynamic calendar, on a listings page, or as a list in the sidebar. You can subscribe to the calendar from iCal (OSX) or Sunbird.
Event Calendar 3 »
External Events Calendar
This plugin is useful for listing speaking engagements, upcoming social events, or other calendar listings which link outside of your site. It adds a special link category for "Events Calendar" with meta fields for location and date. Any links in this category can be displayed through a widget with the option to display all events or only future events, show in ascending/descending order, and options to show or hide link images and descriptions.
Simple Events Calendar
The Simple Events Calendar is a WordPress plugin developed to allow WordPress site owners to easily add upcoming events to their posts or pages. Every event is published and microformated with the hCalendar standard, thus fully semantic.
WordPress Event Calendar
Allows complex calendar management
RSEvents! is the ideal WordPress plugin for everyone organizing events starting from individuals that invite close people to join a party to music bands organizing concerts or companies organizing meetings.
Network Event Calendar
The Network Event Calendar is a very simple Event Listing and Management plugin. What makes this plugin different from the multitude of other plugins that do the same job is that this plugin is WordPress 3.0.1 Multi-Site Network Aware.
Network Event Calendar »
The Events Calendar
The Events Calendar plugin enables you to rapidly create and manage events using the post editor. Features include Google Maps integration as well as default templates such as a calendar grid and event list for streamlined one click installation.
Event Calendar / Scheduler
An easy to implement event calendar plugin built on top of dhtmlxScheduler, which provides Ajax-based scheduling solution similar to Microsoft Outlook Calendar, Apple's iCal or Google Calendar. The plugin allows you to manage single or multiple user events through easy and intuitive dynamic interface.
Events Manager is a full-featured event registration management solution for WordPress based on the principles of flexibility, reliability and powerful features.
Google Calendar Events
Parses Google Calendar feeds and displays the events as a calendar grid or list on a page, post or widget.
Google Calendar Weekly Timetable
Parses Google Calendar Feeds for a week and automatically displays them as weekly timetable in a post. Makes it easy to manage complex schedules in centralized control panel. It's easy to split into subtables (for different cities, groups) and make future changes to timetable.
This WordPress plugin will enable online booking services for your site. Visitors to your site will be able to check availability of apartments, houses, hotel rooms, or services you offer. They can also make reservations and appointments with the ability to choose from multi-day, single day, or by the hour booking.
Event Espresso Lite
Out-of-the-box WordPress event registration, ticketing and management plugin integrated with PayPal for your WordPress blog/website.
Event Express Lite »
Events Calendar Pro
The Events Calendar Premium plugin enables you to rapidly create and manage events using the post editor. Features include Google Maps integration as well as default templates such as a calendar grid and event list for streamlined one click installation.