It's the perfect time to make a lovely herbal bouquet.  Herbs are continually pinched back as we use them, but midsummer is a great time to prune them considerably.  In doing so, they will continue to flourish throughout the season.

Cut them back half way and this will spur new growth, which keeps them bushy and productive.  If you didn't pinch the flowers while they were in bloom, then cut them back by one third.  It's best not to prune them late in the season.