C.W.
Culture Passes are great. If you get on-line the night before you can see which library branches have them checked in. Just search 'culture pass'. There may be more available the day of but if they had them at close they will be there at open. Remember that the library opens at different times on different days now and you may have better luck with a branch on the way to the museum if they are popular at your local one. 10 more minutes in the car is worth free, plus I enjoy having an excuse to check out what the other branches may have on the shelf. Good luck!