At my place of employment, I work almost exclusively with Dell PowerEdge servers. One of the more interesting features, (at least on the ones we have), is the DRAC, (stands for Dell Remote Access Card), basically a little embedded appliance that runs a web-server which, (among other things), gives you access to the console via VNC.
Needless to say, these things are a real life-saver if for some reason you find yourself lacking connectivity to a machine and need out-of-band access to troubleshoot. The problem is that the web UI is flaky as hell, slower than a dog, and very picky about the version of java you're running.
I've tried in the past to use a VNC client to connect directly to the DRAC without success, apparently the version of VNC they use has been hacked to only authenticate through the web UI. However, in the process of googling to see if someone had found a way around, I came across this post on the linux-poweredge mailing list that describes how to enable telnet.
It looks like the telnet interface only provides a subset of the features that the web UI does, but what's important to me is that itdoes support opening a connection to the local console, (the feature I use most, and the one that is the most painful to use from a browser).