OldTVTickets.com displays tickets for filmings/videotapings of television shows–including several sitcom recordings:

oldtvtickets.com/category/sitcoms/

Its author, Mark Evanier, provides interesting commentary on each of the tickets. For example:

Barney Miller tapings were notorious throughout the industry for their marathon hours. It was not uncommon for the evening taping to be followed by a complete rewrite of the script. The audience would depart and the writers would go to work with producer Danny Arnold supervising or doing most of the heavy lifting. Retaping would eventually commence and could easily last until 1 or 2 AM. There were nights when it did not conclude until much later, with some tapings reportedly stretching until dawn. Needless to say, some episodes as aired contained nothing that had been taped before the live audience and were sweetened with canned laughter. But the show was successful and received multiple Emmys, Golden Globes and even a Peabody, so most involved seemed to think it was all worth it.