I use BOINC on several of my computers, it's an easy way to contribute to some good (and interesting) causes.
If you want to set up your RedHat/Fedora (or other) Linux distribution to relay email for you via sendmail, here are some notes.
I used to use Sitelutions for DNS. Here is a small Perl script which I wrote to update my IP address securely. I wanted to use the https protocol with a POST to update the dynamic IP. Nothing very clever really. Make the script executable and then call it at the end of ifup-post - you'll probably find that in /etc/sysconfig/network-scripts/. It is called every time your IP address changes. It could be much improved, if you do let me know!
Here's a little graph showing the performance of my NTP server. It uses a GPS receiver which produces a PPS signal. If you'd like to use a free NTP server that's based in the UK then point your computer at ntp.matthewohare.co.uk
NB! The ms offsets are exaggerated by a factor of 20 on the graph.
I've got lots and lots of SAP HR notes on all sorts of technical (ABAP) and functional (config) topics which I keep meaning to put up here but at the moment I'm too busy. One day I might get the time, keep checking back...