My favorite 4E combat I ran was a room full of Magical Portals to the Abyss that the players had to close whilst fighting the things coming out of them.
They COULD simply bash the portals to death, they had HP and such...but it was far quicker to, as a minor action each turn, try and close the portals through other methods. So I would consider this a use of a skill challenge in the game, as it took multiple successes to close all the portals, and if they didn't succeed in time...well, they'd be overrun.
Made for a VERY tense encounter, as the portals kept getting more and more dangerous each turn.
They COULD simply bash the portals to death, they had HP and such...but it was far quicker to, as a minor action each turn, try and close the portals through other methods. So I would consider this a use of a skill challenge in the game, as it took multiple successes to close all the portals, and if they didn't succeed in time...well, they'd be overrun.
Made for a VERY tense encounter, as the portals kept getting more and more dangerous each turn.