If you're looking for an excursion within six specific U.S. cities, then Google's Field Trip application wants to help you out. Within Portland, LA, Chicago, Washington DC, New York City and San Francisco, Field Trip is offering free entry to a total of 13 different museums.
Field Trip is developed by the Niantic Labs team at Google, and uses your location data to suggest interesting things to do in the area you find yourself in. It isn't surprising to see deals such as this one start to appear, since Google has their own Google Offers service already live. The full list of participating museums is as such:
The offer stands for a 'limited time' with no indication as to what that may mean, and the cards only appear to admit one person for free. So, if you want to go in a group, you'll all need to download Field Trip. When you find yourself in the vicinity of one of these museums, your free entry will appear just as any other Field Trip card. If you haven't yet downloaded Field Trip and this sounds like something for you, grab a copy at the download link below.