According to this
http://dev.rubyonrails.org/ticket/7052
datetime_select should now accept a default value.
However, this does not work when the model does not have a field for the given datetime.
This problem has been encountered by other users on ruby-forum.com
In the following, "trade" is not a model, but simply a field:
This gets the current date time instead of a date with year 1995:
<%= datetime_select :trade, :opened_at, :default => 1995%>
Similarly, this doesn't work:
<%= datetime_select :trade, :opened_at, :start_year => 1995%>
In all cases, the default value displayed by the view is the current time and date.