an interesting thing i learned about parents is that they most definitely DO NOT get your humor. i put up a sketch comedy show a couple summers ago with some friends and we did a couple shows at like 10:30, all to good crowds of friends and people we'd promoted to. Then we did an earlier Sunday at 7:30 show for parents to see. With a crowd of about 30 or more parents/ relatives we BOMBED. at a certain point you reach a critical mass, where there are too many "adults" in the audience, and they're no longer able to just follow along in the laughter of others. now, the other's sheepishly hide thier laughter from the judgement of "adults." jokes that had nailed all week, went silent. fake vomit prompted horror, instead of delight. all in all; terrifying.
so go ahead, invite your parents.... but dont invite too many. in the words of my inimitable best friend/ actor, will smith, "parents just don't understand."