Well it's way to late in the season to start much by seed. I wouldn't even bother with trying with that. Like others have mentioned get started reading and trying something simple. If you want something grand you will have to wait until the spring next year. Gardening forces you to living seasonally like that. You can't hold back the heat or frost if you fall behind.

As far as specific starting plants I would do an herb such as basil and salad greens. Both are simple to buy starters for still at garden store and have a short growing season.