This is the best travel gym. Cheap, available and easy to carry
As I have said here before, I always travel with a deck of standard playing cards. Even with a world class gym in my garage with more equipment than most CrossFit gyms, I still use a deck of cards workout at home. Often, we use a deck of cards when it is raining very hard and a lot of people have to get a workout in a small amount of space. You could train 200 people with a simple deck of cards in a small area.
Here is one variation that I particularly like and one that will certainly challenge anyone:
Red/Black Deck of Cards
All Red Cards= Pushups
All Black Cards= Burpees
Joker 1= 400 m Run
Joker 2= 50 Mountain Climbers
Joker 3= 20 V Ups
Face Cards = 10 reps, Aces= 11 or 1 if you want to scale back a bit, do the face value of all other cards.
This workout could be done in a prison cell, on a dock, or on a Mothership (yes, I did this one on a mothership deep in the Everglades)
Try it...put yourself on the clock and post your time here.
All the best,
Tom Rowland