Participants can book accomodation on their own, either in the vicinity of the university, or in the city center. Look for hotel offers on booking.com or a similar website. The address of the University is Pleinlaan 2, 1050 Brussel (in Dutch) or Avenue de la Plaine 2, 1050 Bruxelles (in French), and it's located a bit outside of the city center in the student neighborhood of Elsene/Ixelles.
We also reserved some rooms for participants at a reduced rate at the U-Residence on campus: http://www.u-residence.be -- 60 euros for a single and 85 euros for a double room, with a discount voucher for the event. If you are interested in staying at U-Residence, please get in touch with the student assistant, Eline Lismont (email@example.com).