First an athletics check to make sure he can do the wall run, fulled by an acrobatics check for the jump flip, than I rolled to see if his opponent got an attack of opportunity (I forget the 4e name), then he would roll his attack and maybe his damage.
I loved it, his dad would always groan and tell him to just "do something normal", and we all hated all the rolling. It was like grappling in 3.5 (or any edition for that matter with grappling rules) something that could make some cool visuals in the style of the game and had some nifty benefits if successful was discouraged because of the time invested into making it happen. At the very least it was five dice rolls and if we had a rules lawyer in the group that week the ability to do such things was even harder due to square counting.
With this in mind and my question from last week about cinematic combat I present Stunts:
Stunts are moves, actions, and effects that take place in combat that differ from the normal actions and attacks that would take place in combat. When a player wants to conduct a stunt ask him or her to roll a d% with a success rate of your choice. Should the player roll over that success rate he or she is successful in his or her stunt.
It is recommended that a stunt start at 20% (10% for base move and 10% for base attack) and increase by 10% for each additional action that the player wishes to accomplish. Please note that a player cannot call for a stunt and just say he or she will hit the enemy multiple times, a stunt needs to be a combination of moves and attacks.
Example: Robert, the Dreaded Thief King of York, wants to throw his dagger at his enemy, run toward the enemy, slid under his legs, spring back up behind the enemy and strike him again. This is 5 actions and would require a stunt roll of 50% or greater to be successful. All Robert has to do now is roll his to-hit and damage.
Stunts are still a little raw, and I've only used them once in an actual game. I will say though that the referee always has the right to say no if he or she believes the player is attempting to abuse the mechanic.