Summer isn't only for fun and relaxation. It's also an opportunity to sharpen your skills. If you haven't already, reserve a spot at one or more mobile, Web development, and business conferences happening over the next few months. Develop your skills, network with other developers, build a better startup, or win fabulous cash and prizes from Samsung. Here's a a list of free and paid upcoming events for Android developers and technology entrepreneurs.

Android DevCon III - May 14 - 17

This promises to be the best in networking and developer training, offering over 75 classes and plenty of Android Developers from Google. Speakers include Christian Kurzke (Google TV Developer Advocate), Shawn Shen (Android Developer Advocate), Les Vogal (Staff Developer Programs Engineer for Google TV), and more.

Information Week Enterprise Mobility - May 17

Bring order to the chaos at this event intended for enterprise developers and IT pros. Make sense of the myriad of devices and middleware development platforms. This one is intended for VPs of IT, CTOs/CIOs CSOs, line of business managers, IT Directors and Managers and other business technology professionals. Developers are also welcome to attend. This is a free, virtual event.

Lean Startup Machine San Francisco - May 25 - 27

This isn't a hackathon or technical development program. Its purpose is to allow attendees to "use Customer Development and Lean Startup principles to validate an idea for a new product or service."  Teams and individuals are welcome. Registration is open until May 24.

Startup 2-Day - June 1-2

In the organizers own words:
"This two-day workshop will furnish you with key concepts, strategies and information that can be immediately applied to your business for demonstrable results. Presented in a lively, informative and hands-on fashion, StartUp 2-Day will provide an outstanding learning opportunity as well as the ability to connect with fellow like-minded entrepreneurial individuals. We look forward to seeing you there.
Registration is still open, and discounts available for teams.

Top Tips for Android UIs - June 16

This is where developers will "learn to create the most appealing and usable apps for your Motorola XOOM tablet, taking advantage of the latest features of Android."  This is a free virtual event hosted by MotoDev.

Angel Hack - June 23 - 24

A national hackathon for entrepreneurs and developers who want to win seed capital. The top two teams will win $25,000. The event is being held in Silicon Valley, Boston, New York, and Seattle. Registration is still open, and reasonably priced too.

Google I/O - June 27 - 29

Put yourself on the bleeding edge of the latest Web and mobile developments practices. Tickets for this event sold out in minutes, but you can watch select recorded sessions 24 hours after live events.

Mobile+Web DevCon - July 17 - 19

This conference is dedicated to iOS, Android, and mobile Web development. Master development tools,  discover best practices, learn how to avoid patent and legal issues, learn to maximize profits in the enterprise app market, and more. Registration is still open for the entire conference or select workshops.

Samsung SmartApp Challenge - May 7 - September 30

This contest is limited to Samsung Galaxy Note and Galaxy Tab apps. Entrants may submit more than one app. Cash and prizes will be awarded in multiple categories. Registration is open until September 30. What developer events will you be attending this summer?  Tell us in the comments below.