It is important to know the coffee shops on campus. I had a lot of programs at the Motley, which is on Scripps campus. Also try the Hub at CMC, the Coop at Pomona and the many others around the different campuses.
For lunch, eating in the dinning halls is not bad at all. The best food on Campus is in Mallott (Scripps). McConnell (Pitzer) has a lot of organic food. They also have a nice meeting room area. Oldenborg (Pomona) is the international dorm, and they have a Hebrew table once a week. This year it was on Mondays. This is also where we have Passover Seders and meals.
If you are looking to get off campus with students, a good coffee shop in the Village is Some Crust. For sandwiches, Full of Life is great, and for Falafel check out Sakas. Some of my most successful events were dinner at Buca di Beppo.
Rooms on Campus can be a little tricky. Since each school has its own bureaucracy, it is different for each school.
CMC- Check out the Athenaeum. They always have wonderful speakers that come, but they also have a smaller room. See if you can co-sponsor a speaker.
Harvey Mudd-Lind has a big screen television that you can use for programs. Low key events are the best kind to have here. In East Dorm every night there is a group of students that watch Star Trek, see if you can bring them Pizza.
PITZER-The Grove house is a great place to have an organic dinner. Also you can use Avery auditorium (the Jewish Acting Group used it for a play)
POMONA-Check out the Smith Campus Center, most rooms are not reserve able, but you can have programs in there anyway. They also have a game room that you can rent out, which has pool tables and many other games. Also, the JCSC office is in Walker, and right done the hall is the Women's Union. They have a wonderful room.
SCRIPPS-Mallott Commons/Sarlo has a great room upstairs. It has a TV and some videos that you can rent. There are also some great lawns to do outside programs on. This is the hardest campus to do anything on. You need to fill out a lot of paper work a couple weeks before you want to do anything.