We are in the final stages of a complete redesign of our various digital library interfaces here at UNT, starting with The Portal to Texas History which has a six year old UI. 

In doing this work I've been poking around at sites that I think are good examples of design for various reasons. 

Here are a few in no specific order:

Calisphere
https://calisphere.org/

Digital Public Library of America
http://dp.la/

UCSD Digital Collections
http://library.ucsd.edu/dc

World Digital Library
https://www.wdl.org/en/

Internet Archive
https://archive.org/

DigitalNC (great interface on top of / beside ContentDM)
https://www.digitalnc.org/

Cooper Hewitt Collections (I like way metadata is presented in a way that isn't just a table with columns)
https://collection.cooperhewitt.org/

Carolina Digital Repository
https://cdr.lib.unc.edu/

North Carolina Digital Collections (great interface on top of / beside ContentDM)
http://digital.ncdcr.gov/

Europeana
http://www.europeana.eu/portal/

NCSU Libraries' Rare and Unique Digital Collections
https://d.lib.ncsu.edu/collections

Hull's Digital Repository
https://hydra.hull.ac.uk/

Those are just a few that I've tagged on Pinboard with DigitalLibraryDesign over the past few months. 

As far as APIs and OAI-PMH I can give some examples that we use here at UNT. 

Each of our collections and partners (as well as the repository as a whole) have a number of API's that we provide.  

Here is an example Partner's page on The Portal to Texas History - 

Abilene Public Library
http://texashistory.unt.edu/explore/partners/ABPL/

You will see a link on the right side to "API" that gets you to this page
http://texashistory.unt.edu/explore/partners/ABPL/api/ that explains the Partner specific apis, oai-pmh, sru endpoints that are offered. 

This is the same case with our collections.  Here is an example for the UNT Digital Library

UNT Scholarly Works
http://digital.library.unt.edu/explore/collections/UNTSW/

and the API page
http://digital.library.unt.edu/explore/collections/UNTSW/api/

Not sure if that is helpful or just too many links. 

Mark
________________________________________
From: Code for Libraries <[log in to unmask]> on behalf of Matt Sherman <[log in to unmask]>
Sent: Saturday, February 27, 2016 4:54 PM
To: [log in to unmask]
Subject: Re: [CODE4LIB] Anyone Doing Interesting Things With Digital Collection Systems?

I'm good with shameless plugs, I was hoping for some to see what awesome
stuff people are working on. This does look pretty cool. Just skimming it
on the train home I really appreciate the responsiveness. I could see where
you could cross walk the bibliographic metadata without much trouble. The
content metadata would harder, though find some folks who want to work with
TEI and you might have some fun with it. Thanks for sharing.
On Feb 27, 2016 5:14 PM, "Gregory Murray" <[log in to unmask]> wrote:

> Matt,
>
> Please have a look at the Theological Commons at Princeton Seminary:
>
> http://commons.ptsem.edu/
>
> It's responsive. Unfortunately we don't have OAI-PMH set up (someday).
> Currently the only "API" is that if you take a URL like
> http://commons.ptsem.edu/id/... and replace "id" with "xml" you get the
> underlying XML document (which is a home-grown schema, not a standard
> library one, embarrassingly).
>
> (End of shameless plug.)
>
> Thanks,
> Greg
>
> Gregory Murray
> Director of Academic Technology and Digital Scholarship Services
> Princeton Theological Seminary Library
> [log in to unmask]
>
>
>
> On 2/27/16, 4:26 PM, "Code for Libraries on behalf of Matt Sherman"
> <[log in to unmask] on behalf of [log in to unmask]> wrote:
>
> >Hi all,
> >
> >I am asking about interesting digital collection tech due to some personal
> >research I am doing.  I have looked a bunch of digital collection sites
> >lately and outside of NYPL <http://digitalcollections.nypl.org/>, I have
> >mostly seen bland, non-responsive but functional CONTENTdm sites or old
> >late 90s early 2000s static HTML exhibit sites.  Given the kind of web
> >tools and UX methods we have now I am curious if people can point me to,
> >or
> >tell me about, more interesting user friendly designs/systems?  I see talk
> >of responsive design and data interoperability via OAI-PMH and APIs, but I
> >must be looking in the wrong places as I am seeing very little evidence of
> >it being put into action.  If anyone can point me to more interesting
> >pastures I would appreciate it.
> >
> >Matt Sherman
>