Easy ease wiggle expression. Found here: http://forums.creativecow.net/readpost/227/10295

easy-ease-wiggle.js

tMin = .25; //minimum segment duration
tMax = .5; //maximum segment duration
minVal = [-50,-50];
maxVal = [50,50];
start=0;
end = 0; 
j = 0; 
while (time >= end){ 
  j ++; 
  seedRandom(j,true); 
  start = end; 
  end += random(tMin,tMax); 
} 
endVal =  random(minVal,maxVal);
seedRandom(j-1,true);
dummy = random(); //this is a throw-away value
startVal =  random(minVal,maxVal);
wig = ease(time,start,end,startVal,endVal);

wig+value;