Go to https://plex.tv/downloads and copy the latest DL link for the proper package and then wget.

Note: There was a major revision change from v0.9 to v1 but I found issues, so I use the link below. 11-13-16


sudo wget "https://downloads.plex.tv/plex-media-server/"
Install via:
sudo dpkg -i plexmediaserver_*.deb && service plexmediaserver start && sudo ufw allow 32400/tcp && sudo ufw allow 32400/udp && service ufw restart

Now configure via:

http://[Local Plex Media Server IP Address]:32400/web