Part of the National University of Singapore . It offers a wide range of courses such as languages, literature, computer studies etc. which are open to the public.

NUS Extension @ Park Mall
9 Penang Road
#12-01 Park Mall (opposite Dhoby Ghaut MRT)
Singapore 238 459
Tel: (65) 6338 8400
Fax: (65) 6339 4560
http://www.nus.edu.sg/nex/Main_personal_enrichment.htm

Ataviz
A useful site for finding classes
www.singaporecourses.com

Singapore Polytechnic
Singapore Polytechnic also offers certain courses for adults
http://www.sp.edu.sg/