Android 3.0 Honeycomb

Andriod Honeycomb was released on 22 February 2011 based on which was based on Linux kernel 2.6.36.

This release is limited to Tablets only.

Changes include:

System Bar: Quick access to notifications, status, and soft navigation buttons available at the bottom of the screen.
Action Bar: Access to contextual options, navigation, widgets, or other types of content at the top of the screen.
Multitasking: Tap Recent Apps in the System Bar, to see snapshots of the tasks underway and quickly jump from one app to another.
Redesigned keyboard: To make entering text fast and accurate on larger screen sizes with greater accuracy and efficiency
Copy/Paste: Simplified, more intuitive.
Browser: Multiple tabs replace browser windows, form auto-fill, and a new “incognito” mode allows anonymous browsing.
Camera: Quick access to exposure, focus, flash, zoom, front-facing camera, time-lapse, and more.
Gallery: View albums and other collections in full-screen mode, with easy access to thumbnails for other photos.
Contacts: New two-pane UI and Fast Scroll to let users easily organize and locate contacts.
Email: New two-pane UI to make viewing and organizing messages more efficient. The app lets users select one or more messages.
Support for video chat using Google Talk
Hardware acceleration.
Support for multi-core processors.

Android 3.1 Honeycomb

UI refinements
Connectivity for USB accessories
Expanded Recent Apps list
Resizeable Home screen widgets
Support for external keyboards and pointing devices
Support for joysticks and gamepads
High-performance Wi-Fi lock maintains high-performance Wi-Fi connections when device screen is off

The 3.1 SDK was released on 10 May 2011.

(Source: Wikipedia)