I'm going to be traveling for the next few weeks but I want to do about an hour work out every day while i do. Does any one have any recommendations for what exercises to do?

Pushups
pullups
situps
supermans
planks
dips between tables or chairs
squats
burpees
go for a run

Use your hotel gym if there is one. If not, pushups, situps, bodyweight squats, basically everything MrS said will do. There are lots of different ways to do pushups. I like adding plyometrics, pushing up off the ground and clapping between reps. Also squat jumps.

MrS, that's a great list. Is this what you mean by 'supermans'?

http://www.exrx.net/WeightExercises/ErectorSpinae/Superman.html

http://www.exrx.net/WeightExercises/ErectorSpinae/ContraLateralSuperman.html

i've been doing them for about a month & they've helped both my back & my posture, especially after nights sleeping in beds other than my own.

These seem like pretty cool exercises, but what are the actual "heavy duty" exercises that are difficult to perform? 1 hand push-ups and 1 leg squats are the only ones I can think of.

Yes, throttle.

You want heavier stuff?
1 hand pushups
1 leg squats (pistol squats)
hand stand pushups
One arm planks
One arm chinups or progressions towards this, like negatives or static holds
towel pullups, terror on the grip
bodyweight tricep extension, one arm if you can
Situp explosively into a squat, so you roll forward hard enough to land on your feet and squat up
glute ham raise
Ab wheel rollouts, standing or knees
Russian twists with arms outstretched holding your weight
Knee raises. These aren't hanging from a bar and raise your knees, aim is to get your knees to your elbows

All of this without equipment, except a bar and a wheel. In fact, **** the wheel.
Dragon flags.
Lying hip swings
v-ups
Pike presses
One legged pushups
Diamond pushups
Divebomber pushups
clap pushups
Double clap pushups
depth plyometric pushups, where you just move your hands from the pushup position onto two objects slightly above the ground like a pair of bricks
same as above but with a full pushup in between.
power overs - pushups explosvely to move one of your hands onto an object like a brick in front of your face, move the other hand over onto it.
Lunge jumps
squat jumps
tuck jumps
knee jumps

That's enough, kiddies.