[Orgmode] Using Times in org-mode calc?

[David Frascone]

I'm trying to make a running log, but I can't seem to get times entered in HH:MM:SS to work right.

Well -- they work right, but I can't get things to re-display in that format.  And, sometimes math is just screwy.

For example:

| Distance |     Time | Time    | Speed | Speed      |
|  (Miles) | HH:MM:SS | Decimal | (MPH) | (Min/Mile) |
|----------+----------+---------+-------+------------|
|      2.0 |    12:34 | 3:17    |       |            |
|        3 |    30:45 |         |       |            |
 #+TBLFM: $3=$2/2

As you can see the 3:17 is some very strange calculation.  Not sure what it did.  If I use "=$2", it returns 6:17

It seemed like it was doing something wright, but, now it looks like maybe it just doesn't understand HH:MM:SS format?

What would be the easiest way to implement something like that table?  Lisp functions?