Welcome to the Tobias-proof guide to installing and configuring your IRC client.
What is an IRC client?
Think of it like a dedicated software for IRC and its chatrooms.
TweetDeck for instance is a Twitter client. GTalk is also a client, but for Google Talk.
The same way you can check Twitter on their website or use GTalk via GMail, you can use a webchat for IRC (probably what you're using right now).
Although it is easy and simple to use a webchat when you are at work or away, it is always nice to come back home to a personal client customized to your needs.
Why you should use an IRC client:
1) Connectivity
You won't need to keep a browser tab open to reach the chan. Your IRC client will be able to be minimized, run in the background or even comfortably rest in your taskbar. No need to keep going back and forth between websites or reconnecting every time you want to join.
2) Awareness
Even if your client is running in the background, you will be instantly notified when someone logs in and/or when a discussion is happening. Never will you miss another conversation about television writing.
3) Logging
Remember that great advice Amy gave you about your spec last week? Neither do I.
Now you don't have to worry about relying on your fragile memory with the introduction of logging. As the name implies, your client will log every conversation going on in the chatroom inside a simple text file (with as much information as you want it to contain). That way, you will easily be able to read back Friday's discussion about fellowships without missing a beat.
And if you're busy/away but your client is running in the background, you will actually be able to log discussions you were not able to attend.
Once configured, your client will be way more convenient and welcoming than any webchat. Plus you will also have some neat features.
Now that you know why you're awesome, let's move on to the actual guide, as easy as 1, 2, 3. In other words: install, configure, profit!
There are many IRC clients available, but for the purpose of this guide, we will be using one of the most popular around: mIRC (for Windows).
For Mac users, try out the even simpler and free Colloquy or Adium.
If you end up using a different client, don't worry, the steps are pretty similar.
Step One: Install the client
Download mIRC and install it.
NOTE: If you're using mIRC, you might have noticed a 30-day expiration warning. Don't worry about it. Even after the trial period has passed, the software will still be working.
Step Two: Configure the client

When you run mIRC you will normally see the window above. This is called the mIRC Options, or Connect window, and allows you to configure/connect to IRC.
You will need to enter something for your Full Name and Email Address.
It is not necessary to enter your real name and email address.
You will then have to choose your Nickname and Alternative nickname.
You can put there your first name or any nickname you would like. As for the alternative nickname, just put the same nickname followed by a _ .
Here is what mIRC will look like once everything is configured and connected:

Now that you've familiarized yourself with the main window, let's continue configuring mIRC, this time adding the server.
First and foremost, go to the "Server" section of the menu. To do that just click on it.
You should get the following window (but with lousy servers instead):

Click the "Add" button on the right of the server menu and add the following information:

Click OK. Once back in the Server list, double-click on TheGreyBox. This will bring you back to the first Configure tab.
All you have to do from there is click the big Connect button, and you're (almost) done.
Step Three: Join the channel
The first time you connect to a server, a small window like the following might pop up:

Uncheck the first box ('Pop up favorites on connect'), and check the second ('Enable join on connect')
Once done, close the pop-up favorite.
If no other channel windows or tabs have opened, only one should be in front of you: the main window (i.e. the server window).
Input the following in the bottom box and hit Enter:
/join #TheGreyBox
Step Four: Enjoy.
A self-explanatory step.
Additional (and optional) Steps
Automatically connecting and joining the channel when mIRC is opened
In the 'mIRC Options' window, go to Connect>Options.
Configure the window as shown here (left side):

Then click on Perform; another window should pop-up.
Configure the window as above (right side).
Click on both OKs. You're all done!
Being visually notified anytime there is a new message/discussion going on in the chatroom
In the 'mIRC Options' window, go to IRC>Options.
Configure the window as such:

Now everytime mIRC is minimized but a message has been posted in the chatroom, mIRC will flash to alert you.
Configuring Logging
In the 'mIRC Options' window, go to IRC>Logging.

The above is how I have my mIRC configured.
Since everything is pretty straight-forward, you can decide if you want to stick with this configuration or change it up.
To modify the folder where your logs will be saved, simply click on the big button under 'Logs and buffer saves folder'.