Great post!
So many people fall into the trap of thinking, well, I cannot go to the gym, so I cannot get a great workout in.
This totally not true!
Does your office have a flight of stairs--make a point to get up from your desk several times through out the day and use them!
Don't have much time before you go to work do this.
Do a set of push-ups--any version will do.
Finish those and knock out set of body weight squats , then drop to the floor and do some back bridges.
Finish off with some knee-ups done off the end of a chair.
As you get stronger up the reps/do another round of the exercises above.
If you happen to have a chin-up bar, you can do those, plus pull-ups as well.
Hope this Helps