It's a museum with exhibits about modern design. It's closed on Wednesday and Thursday. On Sunday, it's free. Sundays are also the day that local craftsmen and artists set up tables in the museum to sell their products.
The museum is located in Maxwell Road, near the URA Gallery (now called Singapore City Gallery, an urban planning museum and exhibit area on the ground floor of the URA government agency which is closed on Sundays).
This is the "hotbed of design & creativity" in Singapore.
Open Monday, Tuesday & Friday: 11am to 6pm
Saturday & Sunday: 11 to 8pm
Adults: SGD 5
Students: SGD 3
Children: SGD 3 (under 12)
Seniors: SGD 3