Hi Patrick,
When I worked at the University of Kentucky we had a team of students who actually did the materials collection in the residence halls. These same students also would do a number of presentations throughout the semester in the residence hall in which they worked (usually in teams of two). These peer to peer education programs greatly increased compliance in the program and cut down on contamination. Typically, the event would be advertised with flyer's hung by the recycling bins with the enticing quality of free pizza and soda in returnable bottles (food always guaranteed a crowd).
It can be helpful to schedule these events in the beginning of the semester to catch the students early. Although many studnets attending had recycled at home, it was surprising to me that for many this was their first opporutnity to recycle daily. Clear signage as you noted is also very important (just make sure it is replaced quickly if damaged).

Best of luck!

Below I've described a few campaigns I remember from my time at Duke.  While I do enjoy the fun of such campaigns, I must say that I think any efforts put into changing behavior need to be well-informed and tailored to the target audience.  Here I'm referring to the process of first identifying the barriers and benefits that your target audience associates with the behavior you want them to make normative.  If the primary barrier to recycling is, for example, that people believe the housekeepers throw all the recyclables in the dumpster anyway, then both of the campaigns described below would be poor choices as neither of them address that barrier.  Anyone interested in learning how to "foster sustainable behavior" should check out Doug McKenzie-Mohr's excellent book, articles, case studies and strategies on this very topic.  Doug's writings have had a strong influence on my thinking about behavior change programs.

Two fun recycling campaigns:

1)  Get Caught Recycling

When I was at Duke, the student group ran a "get caught recycling" campaign where they would randomly pick a person recycling to receive a prize (usually a coupon to a restaurant or something).  The key to running a campaign like that is not the coupon part, however.  It is advertising the fact that the campaign is happening.  If you only have 15 coupons to give out, then only 15 people are going to be touched by the campaign (and maybe the handful of friends they tell about it).  But, if you advertise for the entire month of March that during the month of April people are going to be getting coupons when "caught" recycling, the campaign touches far more people.  So, the real value of the campaign is the excuse it gives you to shamelessly plug recycling with ads or posters or emails that say something like:

5 Good Reasons to Start Recycling Now!

1)  Keeps materials out of landfill
2)  Something else good
3)  Something else good
4)  Something else good
5)  WIN A $20 CERTIFICATE TO MAPLE SPRINGS RESTAURANT!*

* During the month of April, we'll be surprising people that we "catch" recycling with free certificates to local restaurants.  GET CAUGHT RECYCLING!

2)  T-Shirt Pledge Campaign

A lot of what makes up "culture" is values.  Part of sustainability-oriented culture change is getting people to reveal their sustainability values so that others can be influenced by them.  Many people think it's not cool to force their values on others (good) but as a result they unconsciously keep their values secretive (bad).  So, at Duke, we made up t-shirts that we hoped were clever enough that people would wear them for fun and that would reflect that the wearer thought recycling was a good idea.  The t-shirt graphic showed a person tossing a bottle into the trash just before getting struck by lightning with the tagline "Karma recycles".   It was clear the t-shirt pertained to recycling at Duke because it was Duke blue and had the Duke Recycles logo n the front.  We gave the t-shirts away for free to anyone that pledged they recycled.