I want to allow members to purchase a membership on our website that will expire on a particular day. I see in the documentation for the smith cart that you can set the number of days the role will be added but I'm not sure if you support expiration on a fixed day. Any ideas?

That's unfortunate. We are a non-profit organization and our bylaws state that memebrship is from date x to date y. During date Y we have our annual general meeting and new officers chosen etc.. It is unfortunate that this will become a manual process on date y to figure out if someone has enough "days" remaining to continue to be a member. One way that I thought I could leverage the fact that only days can be entered would be to add 365 days whenever some purchases a membership and then on date y check to see if their expiration would cover the next 365 days. Is there another module that can manipulate the expiration date of a security role to set it to be a particular date? That might could be used in conjunction with this module.