CCK time

Use the calculated field module and divide the seconds by 60.

Nancy W.
Drupal Cookbook (for New Drupallers)
Adding Hidden Design or How To notes in your database

Hi lenkkivihko,
if you (or others) are interested in a module for recording 'durations', you can send me a message. I needed the same thing, and build a cck duration field type recently. You can select years/months/days/hours/minutes/seconds from a granularity box, and the data is stored in ISO format for duration. For example P1Y2M3DT4H5M6.78S would be 1 year, 2 months, 3 days, 4 hours, 5 minutes and 6.78 seconds. But any of these could be left blank, so years is for example not required as in date module. Note that the number of seconds can be a decimal, the other elements are integers. A duration field is optionally stored as seconds as well, which can be used for computations. For displaying: either the above ISO format, the number of seconds, or HH:MM:SS for time durations can be used.

I wrote a Duration module - Drupal 6 only (unless someone else backports it to Drupal 5) - that module might be sufficient for this use case, and hopefully others as well :)