Groklaw has reported that Bill Gates took the phone to lobby Mexico to vote for OOXML:
Just to get an idea of the kind of pressure that is being exerted in relation with the vote of Mexico in the ISO with respect to the future of Open XML. It has been divulged that Bill Gates himself got in touch with Felipe Calderón [I prefer the automatic translation, Cauldron :)] in order to have some influence on the position that will be made public in Geneva next Monday. Here the governmental commission is somewhat uncomfortable because of the position of some representatives of the UNAM [the biggest university in Mexico], in particular that of Alejandro Pisanty, former head of Academic Computation Services. He is a respected researcher, very critical of the standard put forward by Microsoft. His strictly theoretical position is for free/libre software.
This is not the first time Bill Gates takes the phone to lobby ISO members. Rumors are running that he also lobbied Denmark, where it is well known that he is a friend of the Prime Minister.