>>172 I've seen people do grip training in cars but I've heard you can't really get solid gains this way because you're too distracted to really get quality reps. But if you just want stuff for the office those grip trainers and extensor bands are small and fit in bags. You might get some side-eyes at the office but people will accept it. Good for train commutes, too. If you want to get big, you need to dedicate quality time to it, not just fit in five second "workouts". It just won't be strenuous enough. You can always fit in extra cardio, though. Park further away from the office. Use the stairs. Jog to wherever you get lunch. It's easy to burn a few extra calories that way.

>>172 Not really sure how you could do this except for really minor stuff like stretching your wrists and stuff.

>>172 Other than that it's grip trainers that comes to mind off the top of my head.