Here's the deal, which runs through this evening and must be used by February 15, 2011.
For $12, you get a museum outing for two adults (up to a $24 value).
For $20, you get a museum outing for a family of four (up to a $40 total value), which includes two adult admissions (up to a $24 value) and two child admissions (up to a $16 value).
To view the deal, click here.