I work in the Network and Telecoms department and was told to set up a second server with CentOS on it. The first one I put a sniffing program on it (Snort, Ntop). Does anyone have any suggestions for a use for the second server? The extent of my knowledge of linux is setting up the first server (also had CentOS). What would be something cool I could put on it?

Are you setting up these servers for the sake of it? Seems a bit odd to build a server without a purpose. A learning process perhaps?

Well you could go for;

A web server with PHP and MySQL support (LAMP).
A mail server or authenticated mail relay for all the desktops.
An LDAP server for company wide address book or company wide login credentials.
A network wide syslog server to collate all the router logs.
A honey pot to lure in and reveal any unwanted guests on the network.

Or perhaps just wire the serial port to the coffee machine so you can gauge whether there’s any coffee left using finger.

Do you know where there are ny guides to do any of those? There's another guy that just set up a mail server for mail relay. I don't know why I set it up. It's a spare server, the boss is gone for a couple weeks, I assume he will tell me what it's for when he gets back. I figure I can have a game plan incase he doesn't have a real plan for it. It may just be in my office so I can learn some Linux.

Try here:
http://www.mysql-apache-php.com/

Helped me set mine up.

Thanks,
//Andrew