Lab and College Culture

We recently got our lab space fubrished with equipment, furniture and almost all other things that are required by research students to flouish. We have a very large space, places for students to sit and work, large white board that can used by the students, couches (multiple), microwave oven and perhaps in the future a fridge.

But there is a problem. The students do not like to sit in the lab space. This is partly because of the culture of the college (most of the labs that I see do not have a lot of students working on their stuff), and partly because these graduate students have access to other places to sit. However, I want them to use this space because I worked very hard to get this from the college admins. Also most of the science is collaborative i.e. most of the ideas that one gets is coming from some other idea in someone else problem.

I want to change the culture. I cannot do it for the whole college but I can certainly do it for my lab. I have a group of positive research students but I don't know how to make them come together in a physical lab space and work.  Or may be I don't know how to do this effectively. What am I suppose to do? Be fun, make the science fun, do X, Y Z.

Any ideas would be welcome.

p.s. I got a major grant from a major federal agency very recently. I am happy.