Mine

exten => s,1,set(__COUNT=1)
exten => s,2,set(__WINNERS=0)
exten => s,3,while($[${WINNERS} < 1])                        ;while we dont have a winner...

exten => s,4,random(1:s,7)                         ;jump out only if we have a winner
exten => s,5,set(__COUNT=$[${COUNT}+1])                           ;if not incrementthe count
exten => s,6,endwhile

exten => s,7,noop(success)
exten => s,8,hangup