To me, In Bruges is one of the best examples of black comedy there is in modern film. McDonagh writes a lot of black comedy in the theatre, which is what I am studying, and his movie outing is just as black. If you can get your hand on a copy of "The Pillowman" (a play) it is one of the best examples of a black comedy I know. The play is about a totalitarian government and child murders, but if done correctly is absolutely hilarious at the same time as being thought provoking.
Tongue in Cheek is harder to do in film. Tons of plays (lots of farces, but also satires or musical adaptations of films) are very tongue in cheek, which to me means an awareness of their own absurdity or self referencing humor, wherein a good portion of the jokes are about the situation. Since film tends more towards naturalism this doesn't translate quite as well.
Maybe The Office, This Is Spinal Tap, O Brother Where Art Thou, and maybe some of Simon Pegg's films like Shaun of the Dead and Hot Fuzz. They poke fun at the zombie and buddy cop genres while remaining fairly true to the genre, unlike blatant parodies which continually make fun of their source material. I mean, the action in Hot Fuzz is still top notch, and Shaun of the Dead still follows a typical zombie movie plot with all the rediculous coincidence and deus ex machina rather than relying on pop culture like Scary Movie.
Again, if you have access to a play store, "Once Upon a Mattress" (Not a porno, I swear) is a hilarious musical that lots of amatuer theatres do which is very tongue in cheek. Makes fun of musicals, fairy tales, and dramatic convention. Quite funny.
Sorry if this was a wall of text.