Davinder Kaur

I have fresh installation of ubuntu 14.04 now. When I updated my system, I faced the following GPG Error:

W: GPG error: http://in.archive.ubuntu.com trusty Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>

As it is saying that “BADSIG 40976EAF437D05B5” signature is invalid. To solve this, I run the following command to import the keys:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6AF0E1940624A220 40976EAF437D05B5

Explanation:

apt-key: It is used to manage the list of keys used by apt to authenticate packages. Packages which have been authenticated using these keys will be considered trusted.
adv: Pass advanced options to gpg. With adv –recv-key you can download the public key.
For more details, read http://manpages.ubuntu.com/manpages/lucid/en/man8/apt-key.8.html

But, it didn’t solve the issue. Then, I found a trick to remove this error. This was like given below:

Open your source.list using your favorite text editor, i.e.

$ sudo vim /etc/apt/sources.list

locate http://in.archive.ubuntu.com/ubuntu and replace it with http://archive.ubuntu.com/ubuntu.

So, I remove the ‘in.’ prefix in each of the addresses to convert them to addresses of the main server. This solved my problem.

Answer by Sanchay Kumar:

15 productive websites to waste your time on online

Getting tired of wasting time surfing Facebook at work? Use your time constructively on any of these 15 websites.

Those days when you sit around your cubicles liking pictures off your Facebook news feed, or scanning 9GAG for a few chuckles, take a leaf from our book and look deeper for something more meaningful. In case you’re too lazy to do that (which we completely understand), we decided to put together a list of websites that put just a little bit of constructiveness into time-wasting:

1. How to do things
How To Do Things – It’s not like this site needs much of an introduction. From subjects ranging from ‘How to throw a great birthday party’ to ‘How to make a wind chime from spoons’ to the unconventional ‘How to fart silently’ and ‘Where to stash your… ahem… sandwiches.’ How To Do Things is a website that teaches you how to do things (no $#!t, Sherlock!).Other than some very entertaining articles, How to Do things does serve to help in unusual situations when you don’t know where to turn.

2. Mathrun
Any website that can make math fun has to be on this list. Mathrun is a website that turns math problems into a test of brain speed, refining your thought processes to think Math.

3. Fiverr
Fiverr is a place where you can hire people for their posted services for the minimal charge of $5. Graphic designers, songwriters, marketing and advertising professionals, you name it. It’s a hub for people to hire freelancers for projects at an affordable price. A go-to website for both the people hiring and people hoping to be hired. Very helpful if you’re interested in personalized DIY options, but don’t really intend to put your own blood sweat and tears in the mix.

4. Spreeder
How fast can you read? Sure, it may be 800-900 words per minute, but reading without understanding or retaining what it is that you are reading is a fundamental mistake made by readers. Spreeder is a basic speed reading software that helps you increase your reading along with comprehension speed of what you’re reading. Which makes it a rather useless skill to have. Spreeder is a speed reading software that allows you to slowly improve upon your reading speed.

5. Classic Short Stories
Sometimes, when you’re bored, you may not really have any time to waste. But you need to get out of your work rut and distract yourself with a short story – Classic Short Stories is a website with a widely appreciated collection of some of the world’s most famous short stories. So if you’re a reader, give this website a gander.

6. Poem Hunter
if you feel like kicking back and concentrating on some random poetry, login and read on! Poem Hunter is a comprehensive online database of published poetry ranging from the classic to the contemporary. Whether you’re looking for John Donne and Shelly or Ray Carver and Paul Auster – Poem Hunter has it.

7. Big Think
Big Think is a website that stands as a constantly evolving road map to the best thinking across the planet — it stands as a valid testament to the the ideas that can help people think flexibly and act decisively in the bid, bad myriad of an ever-expansive world. Always fun to read, with articles spanning various philosophies and life lessons.

8. Ted Ed
Ted Ed is the youtube channel maintained by TED (Technology, Entertainment, Design) the nonprofit devoted to ideas that are worth spreading. Ted Ed, similarly, is a youtube channel made for the sole purpose of educating people worldwide. Though more professionally-based, this TED channel propagates interesting and probable theories. It’s a fun visit.

9. Draw Space
Draw Space is an online portal meant to help the budding artist to learn the basics of drawing and sketching. It is a massive library of free and easily downloadable lessons. These lessons have been authored by world-renowned speakers. Draw Space is a community that consists of over 320,000 drawing enthusiasts, professional artists, art educators, and authors of art books.

10. Duo Lingo
DuoLingo is a website used to learn more than 18 different languages ranging from Italian, Portuguese, Spanish, Korean and several more. Duolingo encourages self-education, and just pushes you teach yourself a new language. Definitely a constructive use of your time.

11. Keyman
There’s a lot to be said about learning new things through the medium of entertainment. There are studies that show that game-based learning surpasses traditional methods of learning with respect to some innate skillsets like strategizing, good hand-eye coordination, etc. Similarly, the smart usage of audio-visual medium also prove extremely effective with respect of information retention, memory enhancement and even great hand-eye co-ordination. Keeping all this in mind, there are some ways the internet can be used to find educational entertainment – specifically, methods that can be used as a source of entertainment and learning as well. Keyman, for example, is a typing game using the classic arcade game Pac Man as a base. The difference between Pac Man and Keyman is the fact that Keyman doesn’t map specific keys for movement. Instead, it assigns random letter keys which change after every use. The result is players frantically hunting for the appropriate key to move Pac Man (or should we say ‘Keyman’?) from the ghost’s path and complete the game. This game comes in handy with people who want to test their muscle memory when it comes to typing on a keyboard. A challenging game, and very effective for people who want to practice typing efficiency.

12. Unplug The TV
Unplug The TV is a website which offers an alternative to television programming. The website is a simple single page that flashes random videos for you to watch as an alternative to the terrible material that is shown on TVs today. The subjects of these videos change from random well-made web series to educational material, to short documentaries and socio-cultural videos.

13. Free Rice
Free Rice is a non-profit website that is owned by and supported by the World Food Programme under the United Nations. As the name suggests, the web portal aims at giving free rice to underpoverished countries. And it relies on the masses to help out. All you need is a decent grip on your English vocabulary. The site throws words at you with four options to indicate their meaning, from which you have to select the most accurate one. Each correct answer donates 10 grains of rice. Improve your vocabulary and help out the needy in one fell swoop.

14. js1k
js1k is a place for coders to test out their skills at javascript. What started off as a joke formulated into a reputed online competition. js1k asks coders to create something innovative using not more than 1kb of java code. Not much scope, you say? Well, it has had some interesting results. From a lightweight chess program to an simulator for Luke Skywalker’s famous Death Star run from ‘A New Hope’. This website showcases all the submitted talent for all to see.

15. Music Theory
Music Theory is a database for anything and everything related to musical research and theory. For people interested in technical questions about music, the site’s a very useful source for information and articles.

Source: 15 productive websites to waste your time on online