Howdy! Parakeets are grass seed specialists which basically means they inhabit dry, arid regions of Australia and forage mostly on dry grass seeds. To be honest with you, parakeets won't be much interested in any thing else than their normal seed diet. I feed mine a source of fresh "spray millet" (which they love) and give them fresh, dark leafy greens daily. They particularly like the entire leaves of Romaine lettuce that I rinse with tap water and throw on the floor of their cages. Even more than eating it, they seem to like rolling and rubbing on the wet leaves to wash them selves. They do end up chewing it up and eating some of it but I think they like taking a bath on it much better.
Just keep in mind that what ever is good for you, is good for your birds. They can eat just about any kind of dark leafy greens, sprouts, boiled eggs, cooked eggs or any thing else you can think of. Even if they don't eat all that though, don't worry! Parakeets survive in some of the harshest habitat in the world. They can go months with out water and feed on nothing but dried up seed heads in the wild. That is what they are adapted for so don't get up set if they don't give in to all your spoilings! Mine look at me like I'm crazy most of the time when I give them treats.
Hope this helps.
CapCityTim
I would like to add that you should not be afraid to try new things. All birds should have variety in there diet and the more you can get them to eat the better. I would also try fruits as well as veggies.
Things to avoid avocado, chocolate, beer, anything with caffeine, anything with large amounts of sugar, etc.
I'm not at home or I'd have a few more links for you as well. I have 7 cockatiels and 1 lovie and they eat just about anything I put in there. 6 of the tiels were rescues on just a seed diet and over time I've gotten them onto a seed & pellet diet with vegies & such.