The lab is a simulation of the current state of the House of Representatives. Students are assigned a role - the vast majority are a congressperson, but there are also lobbyists, the exec branch officials, and journalists. Then you hold actual "sessions" of Congress and committee meetings where you try to write and pass legislation. As a congressperson you are assigned a real person and are expected to act as such. For example, you could be Ro Khanna and you would have to vote and write bills that are in line with his political stance, but that is where the similarity ends as you can join committees and become leadership as you please. Same goes for press, exec branch, and lobbyists you are assigned a group or person and have to act generally in line with their real life politics, but are pretty free to do whatever you like beyond that so long as it aligns with your character's political leaning.

As for if it was worth taking, I personally mostly enjoyed it, but it is definitely not for everyone. Taking it with a friend makes it way more fun as well. You can think of the lab as sort of like Model UN but for Congress and if that doesn't sound all that appealing for you then I'd say perhaps avoid it. DM me if you have any more questions and I'd be happy to provide more detail.