Sorting posts by a date but not the published date?

[brookie]

I am creating posts that refer to events/meetings etc. I would like these posts to appear in featured category post widgets and dynamic menus in the order that the events will take place.

I cannot guarantee that the posts can be created in the right order so cannot use the ID.

Is there a way to sort posts by a custom field?

Or can can I sort by a new field in a custom post type?

I know there are some event plug-ins but all the ones I have looked at give me other problems.