You could also offer to sponsor or have one of your clients sponsor a campaign competition for the students. This is a way to pick up some free new ideas and a way to spot some possible young superstars you might want to hire before anyone else does.
Another good way to spot superior talent is to provide internships in your agency to the marketing and advertising students during the summer when you are short-handed because of holidays. In the US most agencies don't pay their interns. The interns do it for the experience they can put on their CV's. Again, this is a way to "test drive" young talent before you hire.
You can also offer professors an opportunity to come to the agency in the summer for some "real life" experience. They can work on a specific project for a client or new business prospect. Also, as part of the deal, they can give some lectures to your staff after hours.
Another way to keep you name in front of the best students and their professors is to sponsor a cash award each year to the top students in creative and strategic classes.
The point is to have the local university faculty think of your agency as a leader and strong supporter of their education mission. If they do, the professors can recommend you to other businesses in the area for whom they may be consulting. They can establish your name as a preferred employer with their best students. And, the university may even have a budget for their own marketing you could win.
See you on campus.