Tucked away amid the hustle and bustle of Hanover Street, Improv Asylum is easy to overlook. Despite that, the little basement-level comedy club (whose owners opened Laugh Boston in the Seaport last year) consistently sells out its rowdy Friday and Saturday night shows. That’s because of the quality of the improvisers, who are always at the top of their game. Stick around after a Saturday night show for the free (for ticket holders) midnight set, when performers drink onstage and get a little loose. Bonus: On Tuesday nights the “House Teams” (talented improvisers-in-training) perform for just five bucks, so you can spend the cash you save on an extra bucket of ice-cold beer.