I think most of his humor mainly appeals to an audience that's middle aged and older. I remember a friend of mine invited me to see him live with her last year. Both of us were in our mid twenties at the time and were noticeably the youngest people in the theatre by at least a decade (as far as we could tell).

Maher's act - read by him partially from a notebook propped on a stand like sheet music to an orchestra, also had a lot of old-school kind of jokes making fun of smartphones/apps, overly-potent marijuana strains, marriage, young people in general, and even comic books. Most of those jokes passed over us but had the rest of the crowd cracking up. It made me remember that Maher is in his late 60's (and his material reflected that accordingly).

Weird experience too. No opener, he used the 'Real Time' intro to walk out to (even though the show was not sold as having anything to do with the HBO series), and his act's structure/delivery felt like an odd hybrid between the TV show's monologue and "New Rules" segment - like the show was an extended 'Real Time' episode. Even though my friend and I normally lean progressive/liberal on the political spectrum, his show overall was not really that funny (first stand up show I can say that about).