Browser
Easiest way to run Adventure Land is on browsers, however, browsers throttle Javascript performance and timing, so if your code requires heavy processing and precise timing, you will not achieve peak performance with your characters.
Multiple Game Client Windows
Second easiest way is to just open secondary game clients, either at character selection by pressing the "> New Game Window" at the top left column, or by typing /window as a chat command.
Launch Through COM
You can run a specific character faster by opening COM, going to the Characters tab and pressing Deploy on the character you want to run in a new window.
Observe Your Characters!
iFrame Characters
You can start a character as a bot by typing /start CHARACTERNAME in the chat window. From CODE:
start_character("CHARACTERNAME"); // to run the character from within your Code automatically
send_cm("CHARACTERNAME",{a:1,b:2,c:"something"}); // to send messages, objects to your character
// On every character, implement a messaging logic like this:
character.on("cm",function(m){
if(m.name=="CHARACTERNAME") // Make sure the message is from a trusted character
log(m.message); // Do something with the message!
})
Command Line Interface a.k.a. CLI
This is a work in progress, but basically it's possible to run characters on a Raspberry PI etc. too, check out the Advanced article on the topic.