ya if the printing can be done in linux, there is no way to install windows on the pi. and must through USB port, no parallel port available.

and 1 important point is missing, driver for the printer, it must support linux, raspberry pi uses OS called raspbian, its ported from debian, so u might need to search for debian print server. ive never done that, but i dont think its a difficult process, even step by step tutorial are available.

https://wiki.debian.org/SystemPrinting

You did not do any raspi project before yet they asked you to tutor them? then your name precede you. just ask them what they wanted to know

you must be good then 

sifu!!! 

nobody want to hire me as part time tutor 

If you don't want to go for the hardware side,
1. ftp + web server + torrent
2. xbmc

would be a pretty practical usage for the masses

If you want a "wow factor" then most likely it would be some hardware hacks

true that, was using raspi as a download server but in the end changed to my old desktop because of the 100mbps ethernet and limited storage.
........
what's your targeted users? IT students? general masses?

and please, as for any hands on workshop, please ensure that you have a fast internet for all, or else the whole workshop will be a mess(seen and taken a lot of workshops like that)

Not particularly sure about whether there's a script for dyndns but there should be though since dyndns is pretty popular. I'm using ddclient with cloudflare instead.

For public access, just access it via the fqdn that they gave you(usually is ur specified subdomain + the domain that u chosen). But if you're using streamyx <1mbps or any mobile broadband solution then it won't work because they are using private ip.

then............ a bit of modification
1. ftp + web server + torrent(set up web ui) + samba + minidlna + securing it + port forwarding + dyndns
2. xbmc

xbmc is pretty straightforward actually........ so I think the 1st one would be better as it would take more time and it would be a bit harder to do

yeap. that way would be easier but I'm pretty skeptical of those ddns setup anyway. Back to topic, you would go for the internal network setup instead as you would be getting a private ip instead of a public ip. btw, you may want to go to the uni to test things out a few days before the talk because they may block some of the ports that you may need 

not really, you can use the free subdomain that dyndns provides. I used my own domain at cloudflare because I have some in spare. but still, I haven't used dyndns and noip for quite a while already(at least 5 years back?) so it may be a bit outdated.

Samba is a file sharing protocol, and Windows has built in support for it natively(so it is easier than ftp in terms of setup in a sense, but ftp has been around for quite a while so if he/she has been working for a large company then he/she should be more familiar with ftp instead).

yeap. setup wise a bit tedious but at least it is just a one time setup and easier to use imo. anyway, its your call.

I did mentioned the answer at the last line though, which is dd. Here's a link on how to do it: http://raspberrypi.stackexchange.com/quest...my-raspberry-pi