I was replying to a post on the EdTech listserv the other day, when I came up with an idea I like... why not make Webquests using a wiki?
For those of you who teach teachers to create web quests, it gives you a lot more bang for your buck because you are helping them become familiar with wikis while also creating web quests. Your students (and you) will be able to comment on each other's works in progress. And they will see each other's works which may raise the over all level of quality as one good idea leads to another. It would also support teachers working together on the same web quest if you offer that option.
You could create a class wiki and within that create a page for that term. All your students could create a link on that term page to their own web quest wiki, giving your class a one-stop place from which to reach each others' wikis-in-progress.
At the end of the term, you could have them place a link to their wiki on a category page in your wiki (e.g. Science Webquests, Elementary Math Webquests). This would give you an ever-growing library of examples for future classes to explore and build upon.
I think the teachers should create their own wikis (especially since Wikispaces gives teachers free, ad-free) wikis rather than make each of theirs an actual part of your class wiki. That way, they have their own wiki when the class is over. They can continue to add to it, use it with their students, etc.
There is a lot to be said for adding web quests to some of the repositories already in existence, but if you don't do that with your classes, try this-- and let me know how it worked, since I'm not teaching any college courses this year.