Roof-Jumper( CityScape, p. 62)
You can make use of the features of the city as handholds and footholds, defying the pull of gravity.
The Roof-Jumper feat enables the use of the following tactical maneuvers. You cannot benefit from more than one maneuver in the same round. Death from Above: You do substantial damage if you deliberately leap down to attack a foe beneath you. You must drop at least 20 feet. You must roll to hit; this qualifies as a charge attack, with all relevant bonuses and penalties. If you hit, you deal damage as normal, plus an extra 1d6 points for every 10 feet of distance beyond the first 10 feet; thus, a drop of 30 feet causes an extra 2d6 points of damage. You still take whatever damage you would normally take from the fall, but you can reduce the falling damage with a successful Jump check or Tumble check. You cannot use any ability to slow your fall (such as the monk's slow fall ability, or the feather fall spell) while attacking in this manner. Urban Acrobatics: You can make use of windowsills, awnings, lampposts, and similar features of the city when leaping or falling from buildings. If you deliberately jump downward within arm's reach of a wall or similar vertical surface, you can move yourself sideways along the wall. traveling up to 5 feet horizontally for every 10 feet you fall. If you accidentally fall, you can move 5 feet horizontally for every 20 feet you fall. You can move up to your full movement horizontally in this fashion (so long as the wall is wide enough), even if that distance, plus your falling distance, exceeds your normal movement rate.
Falling characters can move in no direction but down.