Last chest workout (Monday) I was wanting to add a little more difficulty to my chest workout, after easily pressing the required reps with the heaviest dumbbell set in my gym (45kg each for those keeping score at home :)). I remember an old favourite I haven't done in a while, the one handed db press.
It's simple to perform, just lie on a flat bench as usual and grab a dumbbell. I recommend using a lower weight than you would with two handed ( I used a 30kg db) and then it's a simple matter of pressing up as you would in a typical two handed db press.
The added difficulty comes because unlike when you use two hands, you're not balanced with a single db so you need to press more slowly. And we know how increased time under tension is better for muscle 'damage'.
Why am I mentioning this now? I was reminded of this when I got up my office chair just now and my midsection (abs, obliques, and Serratus Anterior) told me they hurt rather noticeably (not the case with my normal chest workout of flat barbell bench, incline barbell bench, flat db press). In body building land, this is a good thing :)