Matthew

Event-O-Matic has been rewritten for WordPress 4. View details below.
The Event-O-Matic is an amazing plugin that allows rapid publishing of event listings to your website. Event-O-Matic allows your users to submit their own events and gives you the ability to moderate these events as they arrive to your site. Edit or reject submitted events and add them to your listings for the ultimate social driven event service. Event-O-Matic is also fully integrated with Google Maps to give each event clear location information within your city. View more information <a href="http://garvinmedia.com/eom" rel="nofollow ugc">here</a>.
Other features:
<ul>
<li>Easy media upload for events.</li>
<li>Sidebar widget with upcoming events listings.</li>
<li>Admin Dashboard for quick status previews.</li>
<li>Updated Google Maps Geolocation service.</li>
<li>Exportable to iCal formats</li>
</ul>

Event-O-Matic

Manage submissions to build a community-driven event listing. Allow users to submit events that you can easily review and moderate.

Nagmay

Create maps, drop pins, and so much more!
This plugin adds a new <code>placemark</code> post type that allows author to create and update map content.
The author interface includes:
Place
<ul>
<li>An interactive map to drop and move pins</li>
<li>A way to edit GPS by hand and make use of the geolocation on your mobile phone</li>
<li>An editable set of drop-down lists for picking locations</li>
<li>An alternative text area to describe the location</li>
</ul>
Mark
<ul>
<li>An editable drop-down of marker types and associated icons</li>
<li>An optional title</li>
<li>Optional bubble text</li>
<li>Optional link</li>
</ul>
** Optional ** 
The locations and marker types can be set by an administrator. This allow the you to:
<ul>
<li>Customize the types of markers includeing the image</li>
<li>Set a custom taxonomy for locations, allowing authors to zoom in to campus, building, floor, etc…</li>
<li>Add image overlays to each location, including floorplans. </li>
</ul>
To embed the maps a simple short code is used. You can limit which type of placemarks will show up on each map.
A basic API allows you to pull out the data for other mapping systems.

Placemarks

Allow authors to easily manage placemarks and embed custom maps.

Event-O-Matic vs Placemarks