For the first year of this grant project (Open Source - Open Libraries), we ran our own demo server. But we've now taken down that server because there is a publicly available demo server available courtesty of IMLS grant funds (see IMLS Awards $1 Mil for Open Source for more info about that grant).
There are two demo servers. One is running Evergreen version 2.0.7 (the most recent release). Another is running release candidate 2.1. Brian Feifarek is working on the grant project and maintaining them. He will continue to update both servers with the most current versions and latest release candidates. Please follow the instructions for downloading the correct Windows client associated with whichever version you wish to demo.
See Community Demo Servers on http://evergreen-ils.org/dokuwiki/doku.php?id=community_servers. The ones provided as part of the IMLS grant are indicated (there's also a demo server provided by Equinox Software).
Don't hesitate to contact Brian if you need assistance. His contact info is on the above page.