I have read this entire thread and found it fascinating. I consider myself straight, have never had any serious contact with a man, but am increasingly open to the idea. So:
Masturbation - yes, either side by side or helping each other out.
Active or passive blowjob - would find it easier to receive than give, but would be open to given if I felt comfortable with the person.
Active or passive anal - no; have tried some anal play with my wife and I do not like doing anything anal.
Medical play - yes, except for anal stuff.
Something else - cuddling, massage, frotting, touching, wrestling. I am comfortable being naked with other naked men and 'exploring' different contact possibilities.
To me the most surprising aspect of this thread was the number of men who have done many sexual things with other men but were vehemently opposed to kissing. As a point of interest, my limited contact with men was limited to kissing. It happened twice, and both times we were drinking and buzzed if not completely drunk. One was the result of a dare, the other a lost bet. In each case the kiss included tongue and while we passed it off as a joke / goofy thing to do I know we enjoyed it. To me kissing just seems less intimate and less sexual than playing with someone's anus.