I love love love the Bay Area Discovery Museum in Sausalito. In fact, I like it so much I wrote about it for Family Fun Magazine.
So I was very excited to learn of this deal - which you can buy today only. Buy a coupon for $25 - good for 5 admissions to the museum before 12/31/2010. You do need to use the coupon in one visit (though you can buy more than one coupon - and use two coupons at one visit, and save the rest of the coupons for future visits).
Admissions are normally $10 for adults, $8 for kids. So even if you went with 2 adults and 2 kids, it would cost $36. So maybe you don't save the full 50% every time - but you still save.
To get this deal, click here.