The 15th annual Jingle Bell Festival, to be held on two consecutive weekends, will include a fund-raising walk and a run for the Guinness Book of World Records. On Nov. 30, a 5K Walk/Run will be held at 2:30 p.m., from the Senior Center at 101 Riverside Ave. Proceeds will benefit athletic teams at Medford High and Medford Vocational. For more information, visit Facebook.com/JingleBellWalkRun. After the run, Medford will try to set a Guinness world record for the most people singing Christmas carols while wearing a Santa hat. The crowd will sing “Jingle Bells,” which was written in the city. The event, scheduled for 5 p.m. at City Hall, will be followed by a holiday tree lighting ceremony. Preregistration, a requirement to compete for a Guinness record, can be done at Lonergan Insurance and Real Estate at 74 High St. On Dec. 7 and 8, the festival’s annual house tour will be held. For ticket information, call 781-475-2162. The annual holiday tree raffle will be held at City Hall Dec. 5 through 8. For information on all festival events, go to www.jinglebellfestival.org.