I've been setting up a custom form today, and am using complex formatting. I've set up a thankyou page that prints the questions and responses, and an email that sends the responses.
A couple of the fields are date/time type fields, where I have chosen not to have time. However, the output on the thankyou page and the email both have "–:--:–", where I've chosen not to display time in the form. Is there any way to stop this from happening?
Just curious if there's someone who knows about custom forms and can answer this yet?
My apologies for not responding to this (and the other questions that you bumped) sooner. 
This functionality is currently planned for the 3.5 beta/3.6 stable series; you'll be able to omit any field and Matrix will try to produce at least a semi-legible summary, based on what you have set to show on the form itself - what I mean by this is that if you leave out, say, the month while leaving day and year there, it will try to create something still slightly meaningful. Naturally, the best results will occur with more meaningful omissions, such as seconds or the whole of the time.
(edited for clarity about what what I meant by 'what shows')
Many, many thanks for your replies to this and other messages.
The features in the next release sound promising, and should take care of the problems I've encountered.