Pee-Mail alone is pretty fun... but once you finish yours, and view it, mess around with the numbers in the url to see what other people have written in pee.
Or, just use =0; --e) if (isDigit(L.charAt(e))) { for(s=e-1; s>=0; --s) if (!isDigit(L.charAt(s))) break; break; } ++s; if (e<0) return; oldNum = L.substring(s,e+1); newNum = "" + (parseInt(oldNum,10) + IB); while (newNum.length < oldNum.length) newNum = "0" + newNum; location.href = L.substring(0,s) + newNum + L.slice(e+1); })();">This Bookmarklette to go through the peemails one by one.