Do you own a rice cooker? If so, great! This is super easy. If not, and you want one, here is a little one on sale. If not, and you don't want one, you can do this in a saucepan too, but it takes a bit more attention (stirring, tasting, etc).
Add some rice to the rice cooker pot. (Remember that what you put in dry doubles when it cooks, so proportion accordingly. Add some lentils. Consider how hungry you are, if you're feeding others, side or only dish, etc when adding amounts. I usually do 1/2 cup of each, and end up with some leftovers.
Add a dash of oil, maybe 1 tablespoon if you want a number (olive, veggie, canola). Add a healthy shake of curry powder or soy sauce, salt, pepper, ginger if you want, white pepper if you want, sesame oil if you have it, hot sauce if you want. (Basically, go to town on the seasonings. The rice and lentils are really quite bland without them.
Chop an onion and a pepper if you've got 'em. Toss those in too. If you have some canned diced tomatoes, those make a lovely addition to a curry. Add enough water to cover everything well. Give it a swirl. Turn the rice cooker on, and come back when it's done.
If you want, add chicken or shrimp to the top/side (cooked separately) for a whole meal.