MONDAY A Greek-German Economic Forum is to be held at 1.30 p.m. at the Thessaloniki Chamber of Commerce and Industry. For further details, log on to European Council general assembly. To tomorrow. The Association of Greek Tourist Enterprises (SETE) holds its eighth annual conference on tourism and development at the Divani Caravel Hotel.To tomorrow. For further details, log on to TUESDAY The Center for Renewable Energy Sources (CRES) holds a conference titled «Biogas: A Secure and Viable Energy Source,» to take place at 9 a.m. at the Divani Palace Acropolis Hotel. For details, call 210.660.3321 or log on to The 10th annual event on real estate titled «Prodexpo-Greece and South Eastern Europe» starts at 9 a.m. at Zappeio Hall. To Wednesday. For info, see WEDNESDAY A conference on «Cisco Borderless Networks» starts at 1 p.m. at the Athenaeum Intercontinental Hotel. For details, visit THURSDAY The seventh congress on «Greek Language and Terminology,» starts at 7 p.m. at the University of Athens. To Saturday. The fourth exhibition focusing on photovoltaic systems and renewable energy sources titled «Energy-Photovoltaic 2009» opens at the Mediterranean Exhibition Center in Paeania. Runs to Monday. For further details, call 210.614.1164 or log on to The fifth «Envirotech 2009» focusing on environment, water and green building technologies will take place at the Mediterranean Exhibition Center in Paeania and run through Monday. For further details, call 210.614.1164 or visit FRIDAY The Council for Sustainable Development of the Hellenic Federation of Enterprises (SEV) is hosting an international symposium focusing on water titled «Sustainable Development and Water: A World Challenge for Local Actions,» to take place from 6 p.m. to 9 p.m. at the Athens Concert Hall. To Saturday. For further information, log on to SATURDAY The first WebWorld Expo 2009, an exhibition featuring Internet products and services, opens its doors at Zappeio Hall and will run through Sunday. Opening hours: 11 a.m. to 9 p.m. For details, visit SUNDAY Clocks go back one hour at 4 a.m. to 3 a.m., as European Summer Time ends and Greece officially enters winter time.