How about "Epiphany" or "Momentary Divinity" ("Moment of Divine Inspiration" seemed too long)?
For their turn they get temporary narrative control...they get to be DM, in essence, for that snapshot of time.
The regular DM could/would hold "veto"/approval power, but if you want your players to get creative, then it would seem allowing some latitude would be what you want.
But they can only narrate their own character(s) actions and the results of those actions for that round. (so, no "A volcano bursts from the ground beneath our enemies, roasting them all to blackened husks." or some such.)
I would think turning over the reigns for that singular moment would spark SOME kind of creative thinking/problem solving.
It would, of course, require some maturity and an understanding between the DM and players that it is FOR creativity/"thinking outside the box" use. Things like "In a dazzling whirlwind of bladed fury, I slay them all." isn't really legitimate. But, really, I suppose it could be (as could the volcano example above) if the DM wants to allow it.
Might also provide a fun/interesting challenge for the DM, to have to incorporate what the players come up with...Where did that volcano come from? Why did it fortuitously erupt just then?...Investigation and hilarity ensue.
Obviously...in 4e vernacular, I would give each character one or, peraps better, give ONE for the entire party to induce collective thinking/teamwork for the use of the card. Either way make it/them usable, strictly, only "Once per game session."
Personally, I'd never give this to a gaming group of mine. hahaha. BUT, I don't play 4e. If you are looking to break/shake up how your players think in game, why not give them a piece of the game to think up themselves.
Just an idea.
--Steel Dragons