TV:
Some of these have become cliche, but were revolutionary for the time:
The Bobby Ewing 'it was all just a dream' season of Dallas (spoofed most memorably in 'Newhart' where they ended the series by saying *everything* was a dream of Bob's character in his previous series)
Breaking the 4th wall (having the actors directly address the audience) -- probably best exemplified by Moonlighting, which took it to the next level by having the actors refer to 'breaking the wall' while addressing the audience.
Seinfeld's 'show within a show' where the characters were writing a TV show about themselves.
'Wiseguy' combined the concepts of episodic television and the miniseries and produced what is probably the closest analogue of the RPG 'campaign'. They had two arcs each season, taking 10 or 12 episodes to tell a single story. Very unusual (even today) in that most TV drama is built to resolve itself in a single hour, with small plot strands maybe carrying forward. This concept was perfected, IMHO, by the first couple seasons of Homicide.
Having fictional characters relate to real-life events. The first time I can remember was the episode of WKRP where they react to the Who concert where a number of people were killed.
'24' and its attempt to have the action take place in real-time, with each 1 hour episode covering one hours' worth of events.
RPGS:
Breaking the conventions in an RPG are a little harder. In television, if someone tries it and no one likes it, the show changes or disappears. With an RPG, you have to have the cooperation of the gaming group. I'd think that you'd have to start with one-off sessions, and then go from there depending on the reaction.
Some things to consider:
Probably the biggest convention in an RPG is one player = one character. You could incoporate flashback 'espisodes' where the players set aside their normal characters and played someone else. This works best for groups that are RP heavy and rules savvy. I've done it in the past as a way to let players in a long-running campaign take a little break and do something different. Let the mage play a fighter or vice-versa, etc.
Another big RPG element is the concept of character stats and progression. Some of the fringe elements (LARPS and some other game systems) have done away with these. I don't think I'd be terribly fond of it (and I know my players wouldn't). I'd think you'd have a hard time keeping interest up.
How about the DM-player relationship? I think most of us have played in games where DM responsibilities rotated, but making that a core element of the game could be fun. I've also always wanted to do a Rashomon type thing, where each person in the group took turns DMing the same event, but that might be more interesting in theory than in practice.
Meta-games, with the players playing characters that were playing a game. Scott Kurtz of PvP fame did this in his strip a while back and supposedly is making a real game based on the concept.
Multiple parties / simultaneous action. I ran one once where the party split up, and two DMs in two seperate rooms ran a splinter as they progressed through the adventure with seperate goals. That went over exceptionally well, as each group needed the other to succeed (think end of the world type stuff). Very tense as each group thought they were screwing up and were counting on the other to come to their rescue

We also did one for a while where the other DM and I ran a shared dungeon where two parties were working at cross purposes (similar to the recent Order of the Stick storyline). That was fun for a little while, but having to have one group 'lose' at the end kinda took the wind out of our sails. A neat experiment, but not sustainable.