Some of the comic actors I love best are ones that chew the scenery and the guy who gets my vote for the biggest, gayest performances is England's Kenneth Williams who co-starred in dozens of the Carry On movies. From 1958–1978 sexual innuendo and juvenile humor were gleefully embraced by this gayer-than-gay performer.
This cheapo motion picture series was immensely popular with 2 or 3 being released a year, all starring the same core cast in a new setting - some of the best in the series include Carry On Camping (the gang goes camping), Carry On Nurse (the gang in a hospital setting), and Carry On Teacher (you get the idea). The entire esemble was wonderous, each in their own way, but Kenneth Williams takes the cake with his flamboyant, obliviously closeted homosexual roles.
From a chat show, here's how witty the comic was without a script:
Kenneth Williams passed away in 1988. Here's more on the tragic funnyman from a documentary about the Carry On series.