So maybe this show isn't as much as a "hidden gem" as some of the others, but season 1 is available for instant stream, so yeah.
If you are a fan of Adult Swim's old show Sealab 2021 and the short lived Frisky Dingo will love Archer (Sealab and Frisky were made by the same company, which sadly went out of business). Archer was created by a few of the same people from the former shows. It's much closer to Frisky Dingo in terms of art style and comedy delivery, but the craziness still remains.
For a plot summary, Sterling Archer, Codename "Duchess", is the best black ops field agent in the world... or at least he is extremely lucky when trying to get the job done. When not on the job, he is putting up with his boss, who is also his mother, and an office full of employees that don't care much for office etiquette.
Give it a look if you're bored one day.