Date field with no default value?

I need to add a field where my client can specify the date tickets will go on sale, for a “weblog” containing concert listings.

Note that any concert listing (“weblog entry”) is already making use of the entry date and expiration date fields, as some concerts need to be listed before tickets go on sale.

EE’s standard date field is great, except that it defaults to the current date. I need the field to default to “no date” (like the Expiration Date field). Is there an option for this? Or an extension that adds this type of option?

I am running ee 1.6.8

Moved to Extensions forum by Moderator