The executive summary is that the class went surprisingly well.
The big surprise, to me, was how different UCB's take on improv is from what they teach at the Hideout. We Could Be Heroes teaches improv in the style of Keith Johnstone, a style based on entering the stage with no preconceived ideas, paying close attention to what's going on onstage, and using that to "discover" a story.
So the UCB isn't really about that. Instead, a performer will show up in each scene with a very clear idea what they want the scene to be about. In a longform, they'll start with an "opening", a scene that's designed to generate ideas. The cast might do word-association, or they might bring up an audience member to tell a story. As the opening progresses, the cast will carefully (and mentally) flag funny things in that opening that they can explore later on.
Then they'll use those flagged items as premises for later scenes. And ideally, a performer's opening line will specify precisely what the premise of the scene is, so everyone on stage knows where the scene is going to go.
This is about as far from Johnstone improv as you can get. For Johnstone, walking onstage with the scene already in your head is a cardinal sin, and if everyone onstage knows where the scene is going to go, it's their job to "go there" and move the plot into the *unexpected* thing after that.
Not surprisingly, these two schools of improv (Johnstone and UCB) generate different types of scenes. UCB improv scenes are more like traditional sketch comedy: open with a funny concept, heighten it (or, as Mr. Besser put it, "make the funny thing funnier"), heighten it again, heighten it one last time, and then close on a joke. Johnstone scenes are more story-based -- a protagonist has a status quo, a tilt upsets the status quo, then that sets the protagonist off pursing some goal, and there are complications, the protagonist wins or loses and gets changed in the process.
The Johnstone-types find UCB scenes stilted, shallow, and predictable. The UCB-types find Johnstone scenes meandering, unfunny, and pointlessly arty. Outright West Side Story-style gang warfare between the two camps is always a distinct possibility.
For the moment, I continue to side with Johnstone, just because I don't find the usual sketch-comedy scene structure that funny. I'll always laugh harder at simple character work or verbal wit than a kuh-razy concept -- 90% of the sketches I see are just wacky and boring, and I can't marshal much interest in an improv approach that sets that as its goal.
That said, this class was dead-on fascinating. It didn't teach me much of anything I'll use, but it did a great job of showing me a long, long road that, if I were up to following it for years and years, does go somewhere quite interesting.
Mr. Besser's teaching style was very lecture-heavy. He spent a lot of the three-hour running time explaining where he was coming from, improv-wise -- what style of improv he tries to do, how it's different from Johnstone, and why he thinks the UCB style is worth pursuing.
Then he had students tell anecdotes from their lives (as I said before, this is a common tactic for the opening of a longform) and had the class figure out funny things to explore in the anecdote. From there, he had us toss out possible opening lines based on those funny things, and hashed out whether they worked or didn't work, and why.
It was only in the last hour or so that he had us get up onstage and do scenes based on this. He split the class into halves, and each half took the stage, prompted the 'audience' (the other half) for an anecdote, and had us do some scenes that riffed off of that story.
Since I am a bit of a coward, I sidled into a scene with Chris Allen, whom I trusted to do a good scene. Our anecdote was from a guy who worked as a temp with a breezy startup company equipped with bean bags and lava lamps. So Chris flagged 'beanbags' as funny, and opened a scene at NASA -- he was an official showing me around, pointing out the beanbags laid out for their employees. I played straight man to Chris, as a frustrated military official, and together we stumbled around trying to find ways to make NASA even more inappropriately casual. It was pleasant enough.
At the end of class, Mr. Besser had us go through some typical group word-association exercises that they might use at UCB as a longform opener. You'd all get on stage and play word association ("cat!" "hat!" "bowler!" "strike!"). You'd try to avoid getting stuck in one 'neighborhood' of words ("cut!" "knife!" "sharp!"). You'd occaionally try combining earlier concepts ("blanket!" "pigs!" "capitalists!" "blanket monopoly!"). Also I got the note that, if you pick an obscure word, it's polite to give a brief explanation to your teammates (this after "bumblebee!" "Rimsky-Korsakov!"). And the idea is that, after a couple dozen words or so, you manage to bring things back around to the initial word.
Again, this is an entirely different take from Johnstone. In a word-association game in Johnstone-style improv, you'd just say whatever popped into your head, regardless of whether it was 'right' according to some codex of rules. This was instead very deliberate -- you were supposed to take time to come up with a 'good' word that satisfied those few rules -- so that the chain of words would generate scene premises for later on.
And once we'd gone through that for a while, the three hours were up and the class was done. Again, I don't know how much I'll use this material, but it was an interesting class & I'm glad I attended.
 ... who were lamely renamed "The Heroes of Comedy" a few years back. Bleh to that.
 Mr. Besser repeatedly made the point that, after you heighten the game of the scene (= "make the funny thing funnier"), you have to retrench and explain the basic logic behind what you did. If you've raised the ridiculous thing ("We don't need to run your bag through the airport X-ray") even more ridiculous ("Oh, just take your gun on-board."), you want to come up with some *reason* why this ridiculous thing is so. Going from heightening to heightening to heightening just leads to a mush of silliness.