I absolutely love instant noodles. They're cheap, easy to cook, somewhat tasty, and most importantly, they're endlessly customisable. I've been eating them for years, and the absolute best thing about them is that you can make them completely to suit your tastes and mood.
Technically you're meant to boil them in water and then strain them, but I usually just put them in a bowl and use boiling water from the kettle. I love broth and soggy noodles, so the extra water is a bonus! If this isn't to your taste, you can add the flavouring to the noodles and then strain them, although this will take more time.
A lot of these are more like "mix-ins" than recipes; you can pick and choose multiple to make your own custom instant noodle meal. Using just one will keep it quite light, and using a bunch will make it a super-dense filling meal. Just be mindful of what you can put in the bowl before it overflows!
Here are some of the things I've done with instant noodles; these will seem obvious to some, but I hope they'll be useful to others.
Simple
Add Grated Cheese
Ingredients: Cheese
This is the simplest and what I use a lot; just add some grated cheese (either grated yourself or pre-grated) to the noodles, just after adding the hot water if you're keeping it, or just after straining if you're not. The cheese will melt slightly and add a sort of creamy texture.
Add an egg
Ingredients: Egg
Another classic; just after adding the water, crack a raw egg into the noodles. The hot water (and increased surface area) will cook the egg, and you'll end up with a sort of egg-drop soup. Quite nutritious!
NOTE: Ensure your water is boiling hot if you're using this method, as otherwise the egg may not cook properly. Once, while camping and using a not very good stove, I learned this the hard way.
Add a stock cube
Ingredients: Stock cube
This is a good one if you're not using the flavouring packet that comes with the noodles. Take a stock cube, change size to taste (for a light meal, roughly half a cubic centimetre will work), and just after adding the water (even if you're straining it), pinch it between your fingers to crumble it into the noodles. This will add a lot of flavour (and sodium...) to the noodles.
Add canned meat
Ingredients: Canned meat
Another remarkably simple one; just after adding the water, add some canned meat or fish. I've used tuna, frozen chicken (after defrosting), and even good old spam. This will add a lot of protein to the noodles, and the flavour and texture will become much fuller.
More Complex
Mixed Frozen Vegetables
Ingredients: Frozen vegetables (peas, corn, carrot cubes, etc.)
Good for if you want a lighter or healthier meal. Before working on the noodles, put some frozen vegetables in a bowl and microwave them for roughly a minute per 200g (you want them to be defrosted; there's no actual upper limit on how long you can microwave them for, but they'll get kind of rubbery if you really overdo it). Then, add the noodles and water as normal. The vegetables will add some nice texture, and hopefully some nutrition too!