lazycritter hit most of the high points there so hopefully you can get a few ideas.
In addition to those, I also buy some of that imitation crab and make salads (like chicken or tuna, but sub in the fake crab stuff). I also buy turkey or chicken 'bratwursts'/sausages when they're on sale because they're kind of expensive otherwise. It's still chicken and turkey, but it tastes way different.
I like to sub in cottage cheese or beans with meals too, added protein and the beans have lots of fiber. So even if I'm eating chicken, I might spice it up with some fajita seasoning and add some beans, gives it a taco flavor.
Sometimes a good old protein shake gets me what I need without the hassle of an actual meal. Find one you like and go with it. I'll make a bowl of oatmeal and add protein powder to it, chocolate is especially delicious in oatmeal!