The application comes with an optional keyboard shortcut to enable/disable the touchpad, can automatically disable the touchpad when a mouse is plugged in and more.

App Grid is a new lightweight Ubuntu Software Center alternative that tries to make application discovery easier by using a grid view which includes app screenshots and ratings.

Calibre is an open source tool to manage e-books, which features e-book syncing with popular e-book readers, library management and e-book conversion between various formats. The application is available for Linux, Windows and Mac OS X.

Viber is an application that sits somewhere between Skype and WhatsApp, which can be used to make free calls, send text messages, photos and video messages without having to register (all phone contacts that have installed Viber are listed as Viber contacts).

Initially, Viber was a mobile-only application but a few months ago, a desktop client has been released for OS X and Windows. Earlier this month, Viber Media Inc. has released Viber for Linux as a public beta. For now, there are only 64bit binaries available for download.

The wallpaper pack comes with 18 elegant images, including 3 cool salamander wallpapers:

The application has been updated recently, getting a window mode (previously it was full-screen only) along with other interesting changes. Also, the application now uses GraphicsMagick which means it supports 80+ file types.

Quick update for Numix fans: a new Numix PPA has been created and it hosts daily builds for Numix GTK theme, two Numix icon themes, a Plank theme and even a Numix wallpaper. More Numix related artwork will be added to this PPA in the future.

Furthermore, Numix GTK theme is now compatible with GTK 3.4 and Pantheon (it already supported GTK 3.6 and 3.8), meaning it should work properly in Ubuntu 12.04 and elementary OS 0.2 Luna.

For those not familiar with Evernote, this is a popular note-taking service that besides regular notes, supports images, video and audio, handwritten notes and basically all kind of information you could add to a note. There are Evernote applications for Windows, Mac OS X, iOS, Android, Windows Phone, Blackberry and so on, but not for Linux.

Ubuntu doesn't support tray icons by default and further more, the systray whitelist, which could be used to get applications to use the systray, has been removed with Ubuntu 13.04.

This is pretty bad for TrueCrypt, an open source disk encryption application that still uses a tray icon and doesn't come with an Ubuntu AppIndicator, because you can't bring the mount/dismount dialog up once you close the main window unless you kill the application (it closes to the tray which isn't visible).

For this reason, Stefan Sundin has created an Ubuntu PPA for TrueCrypt which has been patched to use an Ubuntu AppIndicator instead of a tray icon.

The application integrates tightly with the desktop, providing notifications, multimedia keys support, Unity quicklists, Mpris v2 (Ubuntu Sound Menu / GNOME Shell Media Player extension integration) support and more. Other features include last.fm scrobbling, proxy support, Dock Manager integration (integrates with Docky, AWN or DockBarX) and lyrics fetching.

As you probably know, the Nvidia graphics drivers have received initial Optimus support a while back. Currently, the Nvidia GPU can be used to render the desktop, but there's no power saving yet. That means you can for instance play games or watch videos using hardware acceleration.

But to be able to take advantage of this feature in the latest Nvidia drivers, you need up-to-date dependencies (such as Randr 1.4, Xorg 1.13 - that's what the initial Nvidia release notes mention, but it seems you actually need 1.14 -, Linux Kernel 3.9 with some special flags enabled), as well as a custom xorg.conf file and some other bits.

That means that out of the box, the only Ubuntu version that can use this initial Optimus support in the Nvidia graphics drivers is Ubuntu 13.10 Saucy Salamander, but even in Saucy, you need to configure some things to get it to work.

If you're using Ubuntu 13.10 Saucy Salamander or newer, things got a lot easier and you don't need to configure anything to be able to take advantage of this Optimus feature in the Nvidia graphics drivers 319.12+: a package called "nvidia-prime", which comes with a set of tools that enable Nvidia's Prime on MUXless systems, has been uploaded to the Ubuntu 13.10 Saucy Salamander repositories about a month ago and it has currently reached version 0.4 (released today).

Tribler is an open source, decentralized peer-to-peer client based on the BitTorrent protocol, available for Linux, Windows and Mac OS X.

Like other BitTorrent clients, Tribler features a search box you can use to find content however, the search results come directly from other peers, without using a central server and this makes it immune to government anti-piracy attacks (the application will continue to work if the torrent trackers are pulled offline), claims an article from dailymail.co.uk.

The application includes features such as wiki-style channels, video-on-demand (watch videos while you download them) and more.

The tool is free for personal use (1-3 teammates), with unlimited syncing and 1 collaboration folder or, if you want unlimited collaborators, you must pay a fee of $10 per teammate/month. AeroFS is available for Linux, Windows, Mac OS X and Android.

For now, Unity 8 is in its early alpha stages and not ready for use, and in fact, there's a message on the wallpaper used by it that says just that:

Tiny Tiny RSS is an open source web-based RSS reader that you can install on a server and then access it from multiple computers/devices. Since it's self-hosted, you're in control of your data and don't have to worry that the service may be discontinued, like it happened with Google Reader (and almost happened with The Old Reader).

The Intel Linux Graphics Installer is a tool developed by Intel that allows users to easily upgrade to the latest graphics drivers for Intel hardware. The installer automatically adds a repository used for upgrading the packages provided by Intel - that means that besides the Intel Linux Graphics Installer, you can also use the Ubuntu Software Updater, apt-get, etc. to upgrade the packages.