My reply to this is YES, there are a ton of exercises that one can do while traveling without access to a gym. Here is a list of what I know off the top of my head, but believe me there are definitely a lot more, you just have use your imagination and be creative.
1) Push-ups (chest, triceps, shoulders and core are the primary muscle groups worked)
2) Dips (done between two chairs, tables, beds, or whatever other stationary objects may be present) - primary muscle groups worked are: triceps, secondary are shoulders and upper back.
3) Using an exercise band, which can be bought at Wal-Mart for cheap, one can perform a huge variety of exercises including:
Side Laterals for medial shoulders
Front Raises for anterior shoulders
Bent-over side raises for rear shoulders
Curls for biceps
Tricep kick backs
Bent-over rows for back
...and many more.
4) Using any small object, one can hold it out in front of them and do
walking lunges - either in place or one step at a time (if enough room permits).
5) One can also do wall squats - Pretty self explanatory
Lean up against any wall and then do squats, using the wall for stabilization. You can also do these with a small object held out in front of you without using a wall, if your balance is good enough.
The above are just a few great exercises that can be done in the comfort of your own hotel room or elseware, without the need for a gym while traveling.