I contacted Wyeast and asked them about Pacman and they said "Your favorite homebrew shop may order Pacman year round through Brewcraft USA in Portland, Oregon."
I use Fermcap - it affects surface tension and greatly reduces blowoff. (Also prevents boil overs ). But moreover, during active fermentation there is positive pressure in the carboy so all you really need to guard against is chunky stuff (stuff big enough to see) falling in. I just put...
Check out the Fox - on the opposite side of the street from the 'shroom. Eight taps - no BMC - Fuller's ESB, Hobgoblin, Holy Grail, Sierra Nevada Porter, among others. Pints 3.50 - 2.50 during Happy Hour. Great food as well.