Just as a recommendation, your two sons will probably want to have
another two players with them, just for the usual four person team.
Find some other home-schoolers or some such thing. Your kids are also
pretty young, so I can't really tell you anything about the middle
school scene in Michigan, and, being from Georgia, I know only a
little more about the high school scene. If you want to check out
some tournaments, try www.hsquizbowl.org it's a pretty large list of
tournaments across the country. Of course, at 10 and 12 they're a
little young for high school.