I post plenty of heads ups on free mp3s, but this one is a bigger deal. The Bay Area's The Sippy Cups have managed to get themselves the first free iTunes download in the Children's Music category. For the next week, iTunes users can go here to download "Seven is the New 14," one of the better (and funnier) tracks from their new album The Time Machine. ("Three and three? Not seven.") I expect a lot of clueless comments on iTunes from folks who aren't really part of the kids music demographic, but I think most readers here are going to like it. The Time Machine is out today as an iTunes exclusive, next week everywhere.