Tales of an Admin
I must say, though this is my first full-time admin job, Ubuntu has been painless for the most part. I create two images: one for the HPs and one for the Lenovo. This means I only need to do everything twice, and then I simply use PING and an external hard drive to place the images on each of the machines. Though as stated, admnining has been mostly painless, one of my HPs has some bizarre issue and PING fails to load the image each time, and though I have tried and tried, I think it is some combination of bad hard drives and BIOS issues that will not resolve. Eventually I get it on, but the machine is never quite right and is currently down for maintenance as we speak, but this is no issue with Ubuntu. I then have a second machine, a Lenovo, which I have not diagnosed, as it just came down two days ago. I am hoping a simple re-image fixes it.
Having all the repositories locally also makes software installation a snap. I simply install whatever I need on the original image machine without needing to worry about spending money paying for megabytes on my personal modem (as getting my institution to pay for any form of Internet is near impossible). This allows me to add seemingly superfluous applications which may be useful later on. This way I do not need to re-image every machine if a few months later I want to add a new app. Remember, I do not have a full network, so any form of remote-management or local-server-based repositories for new applications is not possible. All management must be done by hand, and usually involves me armed with a script and a flash disk going machine to machine making changes.
One Computer at a Time 
Great post on some of the problems with ITC in Africa. USB viruses are the bane of all volunteers existence. Do you have all your teachers put an autorun.inf folder on the drive? At least stops the virus from spreading.
The distribution model of Linux is horribly suited for the low bandwidth experienced here, but when I used it back home in the States it was amazing! The amount of FLOSS software that is out there is amazing. Though not all of it lives up to professional standards that are definitely sufficient for everyday use. One thing I really want to do here is a photo editing class using GIMP, but the right combination of motivation and timing from my counter parts hasn’t happened yet.
Have you looked into the games available in the Ubuntu repos. Might be another good way to get people to try them out. Personal I like simple logic games like those found in the package sgt-puzzles, but there are tons of 3-D games too.
Thanks for the link to Camera.ie. Looks like a cool organization, need to look into it more.