And then, just for the sake of completeness, I OED'd it. To my dismay, museum is listed as a verb. An intransitive verb, meaning to visit museums (n.). Here is one of the three exemplary quotations in the OED:
1899 H. James Let. 2 Apr. (1984) IV. 101, I breakfasted, dined, theatre'd, museumed, walked and talked them.The them at the end suggests that all six verbs were being used transitively, which makes it a poor example of museum as an intransitive verb. I understand that the usages here may be eccentric, but that's irrelevant to my point (except that it may [or may not] mean that it isn't a good exemplary quotation for any purpose at all).