The wrist roller is a proven grip and forearm builder. Ramp up the time under tension by standing on a step. Shoot for 30-60 seconds of constant tension.
We usually train thinking of reps, but sometimes it's better to think of time under tension or TUT. Take the wrist roller exercise. Do it on a high step to maximize the distance. The weight won't have a chance to rest on the floor and you'll keep the tension constant – one of the key ingredients of muscle growth.
Now go for time. Start with 30 seconds (15 seconds up, 15 seconds down). Make it a goal to hit the one-minute mark. It doesn't matter how many "reps" you do, just hit 60 seconds.
You finished boozing it up over the holiday? Good. Cuz it's time to put what's left of your brain matter to use in understanding the nervous system and how utilizing it can make you stronger and better lookin'.