LambdaMOO is a classic text-based virtual environment.
Xenoblood have some emergent spaces in LambdaMOO + you can join them to explore, play, build, code.
Below are some basic instructions to get you started.
There is a more comprehensive guide to lambdaMOO here.
To connect to LambdaMOO you can use the embedded Telnet link or use a dedicated MOO client. These are links to download Telnet clients for Mac and Windows below.

If you are connecting via the direct link below:
Once you have connected you will see the welcome message. At this point type:
connect Guest

then

@join Alabaster.Shimmer

If you are connecting Via MOO Client (Savitar or MUSHclient):
In your dedicated MOO client, you will need to enter the following details:
Host: lambda.moo.mud.org
Port: 8888
Connection Command: connect Guest

then

@join Alabaster.Shimmer

Direct link to LambdaMoo
download telnet client savitar for mac
download telnet client mushclient for windows