new tricks in minecraft

speed
/effect @p[-823,31,-413,dx=0,dy=0,dz=61] 1 2 2 true

kills fireball
/kill @e[-872,77,-417,dx=0,dy=10,dz=100,type=Fireball]

detect item
/testfor @e[type=Item,c=1] {Item:{id:minecraft:wool,Damage:4s}}

shoot when jumping
/execute @p[-823,31,-413,dx=0,dy=0,dz=61,score_jump_min=1] ~ ~ ~ summon Fireball ~-49 ~1 ~-1 {ExplosionPower:2,direction:[0.0,3.0,0.0],Age:2}