TCL 8.5 (71 70 68) (67)
TCL has no real chance of ever winning, but it is a fun way to oil the machine:
proc c x {while \$x>1 {set x [expr $x%2?3*$x+1:$x/2];incr k};set k}
formatted for readability:
proc c x {
while {$x>1} {
set x [expr $x%2 ? 3*$x+1 : $x/2]
incr k
}
set k
}
Edits: many suggestions (inspired) by sergiol. I guess the answer is more histheirs than mine, by now :-)