Above is the web address for the University of Colorado Off-Campus Housing and Neighborhood Relations home page. They have a resources for students looking for housing /roomates. To view "Ralphie's List" of available housing options you will need to contact the office for a guest account.
I know the University owns some apartments in the Williams Village area called Bear Creek Apts. They may have others. On campus, Willard Hall has a floor dedicated to Sophomores. My son and his friends found their apartment through a realty company that also manages rental properties. Good luck!
Location: University Memorial Center, room 313
Hours: During the school year our office is open from 8:00 am - 5:00 pm and during the summer, 7:30 am - 4:30 pm.
"Our office maintains listings of rooms, houses, apartments, and roommate requests and provides students with Boulder maps, copies of the Boulder Tenants' Guide, the Boulder Model Lease, subleasing and roommate agreements, furniture rental information, moving tips and other materials related to living off campus. Students can also schedule an appointment with our lawyer on Tuesdays or Fridays to discuss rental concerns.
*Note: Off-Campus Housing & Neighborhood Relations is funded by CUSG. Services are for fee-paying students. If you are a parent or a TRANSFER STUDENT (caps mine)and would like access to Ralphie's List you will need to request approval for a guest account."