I want to simulate user activity on a virtual machine in a completely automated maner. That is, I would like to run a program or a set of scripts that would simulate an user using a computer for an indefinite amount of time (say, simulate an office worker - write some random files, open some files, check webpages, etc.)

Basically, I'm simulating an internal network over a set of virtual machines and would like to add some activity to the network to make it more realistic.

Is there a program or a set of scripts out there that could do the described job?

I was thinking that network testing tools might be of help, but would a set of those be enough to simulate activity on different aplications (say, mail servers, ldap server, nfs, apache, etc.) ?

Any advice on how to acomplish this?

Thank you