How to Set up WiFi Access Point to Share Folder of Files for Download? I need to set up a WiFi access point that can offering file downloading via web browser using what I will call a "DEVICE" here for short.  

I am open to what the device will be -- my MacBook Pro, a 2nd MacBook Pro I also own, a wide-squat Time Machine I own, another device I have not yet purchased, or one of those devices augmented with a new purchase -- I just want to achive the goals mentioned below.

I am also interested in the DEVICE being somewhat to very portable, if possible.

So I need a DEVICE that will not (necessarily) be connected to the Internet but that will allow people in the same room to connect from their computers via the DEVICE's WiFi and then visit the one website hosted by the DEVICE whose domain hostname will be served via domain name server on the DEVICE where they will see a webpage with links to and descriptions of files they can download via HTTP.

My use-case is I will be speaking at numerous WordPress conferences and I want to show people how to set up a local development environment during a 45 minute talk. More importantly I want those who are interested to be able to follow along in semi-workshop format and be able to configure on their own computers.  

The problem is the people installing on their own machines will need to download ~750MB and if that takes more than 2 or 3 minutes for 10 to 20 people to download I will almost certainly run out of time.

I am very technical and I feel like I can envision numerous solutions but cannot quite confirm the details of any one solution.  I had purchased a LibraryBox but after testing it takes more than 10 minutes to download the software, and that is with only one computer connected. Obviously this is a non-starter.

I am happy to buy a WiFi dongle to complete my DEVICE if needed, or even a completely non-Mac DEVICE to carry with me, I just need to make sure whatever I do can:


Allow many WiFi connections, 
Is very performant, 
Has files that can be made available for download via HTTP,
Does not open my laptop up to any security concerns, and 
if possible that is reasonably portable, e.g. the Time Machine is on the "almost not portable" end of the spectrum.


Thanks in advance for any help.

UPDATE:

Looking at one of these wondering if it would allow me to present my MacBook at the file server, but can't tell from the available information.
You can probably do this on your Mac book with an Ad-Hoc network, but I don't know how the performance will be with 20 users so purchasing a separate wifi access point (AP) is probably a good idea (Apple's Airport Express is very portable).  In either case, you will want to setup a web (Apache) and DNS (Bind) server on your laptop.  That is pretty easy to do if you purchase Apple's server application.  (It is possible to do both without purchasing the server, but requires more technical skill.)  Configure the dhcp settings on your AP to give out your computers IP for DNS.  For that to work, you'll also need to configure the AP to always give your computer the same IP address when it connects.  Then, when clients connect to the AP, you can give them your website and they will be able to download files.  

Total cost, approximately $120.

This is really only a high level description.  You may need to ask more specific questions as you get into it and need help.