Well first there are CP's that go dorment such as the American plants (venus flytraps, certain USA sundews) and there are also those tropical types that grow year round.
Since this is a new project you would also want the hardier types, suggestions would be Drosera Capensis (Cape Sundew), Drosera Alicia (Alice Sundew) Nepenthese Ventricosa or Alata (these are Asian Pitcher plants).

If however you could allow plant to go dorment (in nature they are subject to the less light of winter and the cold, they can tolerate up to 20 F roughly) then things such as VFT's would be fine, many people use things like fridges for dormency if they are in an area which does not get any icey winters.

If this was a permenent fixture for the class I think tropical plants would be easier.
Of these I think like I suggested, a D. Capensis or 2 would be a must, the kids would go wild to see the leaf wrap itself around its prey.
The Nepenthes are beutiful, I have a N. Ventricosa which is very tough and is a stunning plant, the pitchers are a nice pink in colour.

So if I was you, the ones that pop to mind for ease of growing and ease of propegation would be these three (sure you will get many more suggestions):
1) Drosera Capensis (try and get a Broad Leaf mutation, they are awesome, you also get Alba (which is all white tentacles and white flower), Typical (which has red tentacles and a thnner leaf that Broad Leaf) and All Red (which can turn completely red in colour)
2) Drosera Alicia, the Alice Sundew is also from the Cape of Southern Africa (my home originally), they are rounded rosettes of beutiful leaves that turn a loverly red in colour and glisen under light.
They spread fast via plantlets from the roots and from seed.
3) Either a Nepenthese Ventricosa or Nepenthese Alata (or a cross between them)
These Pitcher plants however unlike the sundews do not like their roots sitting in water, so if you have a "hill like" effect running down your tank you would put this plant up top where water could drain away from the roots to the lower plants which would be the drosera that dont mind wetter conditions.

I would suggest a good layer of pure Perlite at the bottom of the fish tank, then the layer above (rest of mix) is a 50/50 mix of Sphagnum Peat Moss and Perlite, the Sphagnum Peat is acidic and not rich in nutrients which CP's like, the 50% Perlite Mix allows for drainige and the bottom layer of Perlite absorbs the excess drainage.
Then a top layer can be Sphagnum Moss which helps humidity and retains water.

Hope this helps, feel free to ask more questions!!

Cheers n good luck

Sheldon

Hi

Just so you can see what plants Im on about, here are some pics:

D. Alicia (Alice Sundew)
{{gwi:561514}}D. Capensis (TYPICAL VERSION)
{{gwi:561515}}Heres one eating(this is the ALL RED version)
{{gwi:561516}}Heres the "ALBA"(all white) version:
{{gwi:561517}}And finally the BROAD LEAF version:
I personally get my stuff from www.cobraplant.com, they are great great guys.
If they dont have some things in stock, then www.flytraps.com is also a good supplier and has some good prices.

Cheers

Sheldon

And of course I forget 1 or 2 of them.
Here is the Nepenthese Ventricosa: (I really love my one, GREAT PLANT!!!)
{{gwi:561518}}And as promised, the Nepenthese Alata:
{{gwi:561519}}And then there is always a cross between the two N. Ventricosa X Alata:
{{gwi:561520}}Cheers

Sheldon