There is this popular job interview question:
Given a machine hangup (let's say RHEL) how do you trouble shoot the problem?
My answer would be:
1) I'd use (what is the name of that server BIOS which allows you to connect to its console?) or go down to the server room and connect a monitor and keyboard to it and login as root.
2) Then I'd run "top" to see if some process has a very high CPU usage
3) Then I'd check memory (by "top" again?) and the total number of processes ("ps uawx") and the system limit (how, would "limit" give me the correct number)?
And then I don't know. Maybe run "vm"? But what would it tell me?
Please give me few good advices and impressive sentences for the recruiter.